2c:null 2d:["$","title",null,{"children":"Air Quality during COVID-19 Lockdown in India | వీవెన్ | Observable"}] 32:T619,chart = { const svg = d3.create('svg') .attr('viewBox', [0, 0, width, height]) .style('background-color', 'white') ; drawAqiLevels(svg); svg.append('g') .attr('transform', 'translate(0, '+ y.range()[0] + ')') .call(d3.axisBottom(x).tickFormat(d3.timeFormat('%I %p')).ticks(d3.timeHour)) .selectAll('text').select(function(d, i) {return i === 0 || i%2 ? this : null }).remove() ; svg.append('g') .attr('transform', 'translate(' + margin.left + ', 0)') .call((d3.axisLeft(y).tickSize(16))) .select('.domain').remove() drawLines(svg); svg.append('g').attr('transform', 'translate(' + margin.left + ', 16)') .append('text').text(city) .attr('dx', 16) .style('font', '12px sans-serif') .style('font-weight', 'bold') .style('text-shadow', '1px 1px 0 white, 1px -1px 0 white, -1px 1px 0 white, -1px -1px 0 white') .append('tspan').text(' (' + locations.get(+location).name +')') .style('font-weight', 'normal') ; svg.append('g').attr('transform', 'translate(' + margin.left + ', 38)') .append('text').text(parameters.filter(p => p.parameter == parameter)[0].displayName) .attr('dx', 16) .style('font-family', 'sans-serif') .style('font-weight', 'bold') .style('font-size', '12px') .style('text-shadow', '1px 1px 0 white, 1px -1px 0 white, -1px 1px 0 white, -1px -1px 0 white') .append('tspan').text(data.length ? '': ' — No data! Choose another station.') .style('fill', data.length ? 'transparent': 'red') ; return svg.node(); }33:T7e1,{ const w = width * .6; const height = 42; const margin = {top: 0, right: 12, bottom: 16, left: 6}; const svg = d3.create('svg') .attr('width', w) .attr('height', height) const xDate = d3.scaleTime(d3.extent(data, d => d.date), [margin.left, w - margin.right]); svg.append('g').attr('transform', 'translate(0,' + (height - margin.bottom) + ')') .call(d3.axisBottom(xDate)) .select('.domain').remove() svg.append('g').selectAll('line').data(d3.timeDays(d3.min(data, d => d.date), new Date())).join('line') .attr('x1', d => xDate(d)) .attr('x2', d => xDate(new Date(d.valueOf() + 24 * hour))) .attr('y1', height - margin.bottom - 6) .attr('y2', height - margin.bottom - 6) .attr('stroke', d => color(d)) .attr('stroke-width', 4) svg.append('g').attr('transform', 'translate(' + margin.left + ',' + (height - margin.bottom - 8) + ')') .append('text') .text('Before Lockdown') .attr('dx', 4) .attr('dy', -6) .style('font-size', '11px') .style('font-weight', 'bold') .style('font-family', 'sans-serif') ; svg.append('g') .attr('transform', 'translate(' + xDate(new Date('2020-03-25')) + ', ' + (height - margin.bottom - 8) + ')') .append('line') .attr('y2', -16) .attr('stroke', '#000') .select(function() {return this.parentNode}) .append('text') .text('During Lockdown') .attr('dx', 4) .attr('dy', -6) .style('font-size', '11px') .style('font-weight', 'bold') .style('font-family', 'sans-serif') ; svg.append('g') .attr('transform', 'translate(' + xDate(new Date('2020-05-18')) + ', ' + (height - margin.bottom - 8) + ')') .append('line') .attr('y2', -16) .attr('stroke', '#000') .select(function() {return this.parentNode}) .append('text') .text('Post relaxations') .attr('dx', 4) .attr('dy', -6) .style('font-size', '11px') .style('font-weight', 'bold') .style('font-family', 'sans-serif') ; return svg.node(); }34:T714,aqi = new Map([ ['no2', [ {low: 0, high: 40, color: '#1a9850'} , {low: 40, high: 80, color: '#91cf60'} , {low: 80, high: 180, color: '#dddd11'} , {low: 180, high: 280, color: '#fea033'} , {low: 280, high: 400, color: '#fc3311'} , {low: 400, high: 10000, color: '#aa0000'} ] ] , ['bc', []] , ['co', [ {low: 0, high: 1000, color: '#1a9850'} , {low: 1000, high: 2000, color: '#91cf60'} , {low: 2000, high: 10000, color: '#dddd11'} , {low: 10000, high: 17000, color: '#fea033'} , {low: 17000, high: 34000, color: '#fc3311'} , {low: 34000, high: 1000000, color: '#aa0000'} ]] , ['pm25', [ {low: 0, high: 30, color: '#1a9850'} , {low: 30, high: 60, color: '#91cf60'} , {low: 60, high: 90, color: '#dddd11'} , {low: 90, high: 120, color: '#fea033'} , {low: 120, high: 250, color: '#fc3311'} , {low: 250, high: 10000, color: '#aa0000'} ]] , ['pm10', [ {low: 0, high: 50, color: '#1a9850'} , {low: 50, high: 100, color: '#91cf60'} , {low: 100, high: 250, color: '#dddd11'} , {low: 250, high: 350, color: '#fea033'} , {low: 350, high: 430, color: '#fc3311'} , {low: 430, high: 10000, color: '#aa0000'} ]] , ['so2', [ {low: 0, high: 40, color: '#1a9850'} , {low: 40, high: 80, color: '#91cf60'} , {low: 80, high: 380, color: '#dddd11'} , {low: 380, high: 800, color: '#fea033'} , {low: 800, high: 1600, color: '#fc3311'} , {low: 1600, high: 10000, color: '#aa0000'} ]] , ['o3', [ {low: 0, high: 50, color: '#1a9850'} , {low: 50, high: 100, color: '#91cf60'} , {low: 100, high: 168, color: '#dddd11'} , {low: 168, high: 208, color: '#fea033'} , {low: 208, high: 748, color: '#fc3311'} , {low: 748, high: 10000, color: '#aa0000'} ]] ])35:[] 30:{"id":"e7a283d724cfc5a6","slug":"air-quality-during-covid-19-lockdown-in-india","title":"Air Quality during COVID-19 Lockdown in India","thumbnail":"42aeab027f622bbf36d603585452780011a6f6e5b1a29ad235ced6d921460a0d","access_level":"public","create_time":"$D2020-03-31T15:31:48.306Z","update_time":"$D2021-05-18T07:23:11.192Z","view_time":null,"first_public_time":"$D2020-04-01T19:49:35.585Z","has_unpublished_edits":null,"fork":false,"stars":1,"starred":false,"owner":{"type":"team","id":"9072823fe9d379f2","login":"veeven","name":"వీవెన్","avatar_url":"https://avatars-next.observableusercontent.com/c857fc38aefa0e86178487179f5b3ee50a45c0bf0b00ab6d89a34d096a9dfbf0","tier":"starter_2024","bio":"Free software & Telugu"},"version":1258,"publish_version":1258,"role":null,"authored":false,"authors":[{"type":"individual","id":"ad0d391dc4298470","login":"veeven","name":"వీవెన్","avatar_url":"https://avatars-next.observableusercontent.com/c857fc38aefa0e86178487179f5b3ee50a45c0bf0b00ab6d89a34d096a9dfbf0","tier":null,"bio":"Free software & Telugu"}],"members":[{"type":"individual","id":"ad0d391dc4298470","login":"veeven","name":"వీవెన్","avatar_url":"https://avatars-next.observableusercontent.com/c857fc38aefa0e86178487179f5b3ee50a45c0bf0b00ab6d89a34d096a9dfbf0","tier":null,"role":"editor"}],"comments":[],"custom_thumbnail":false,"trashed":false,"lapsed":null,"subscribed":null,"forks":0,"collection":null,"type":"notebook","body":{"titling":"auto","title":"Air Quality during COVID-19 Lockdown in India","cells":[{"id":0,"value":"md`\n# Air Quality during COVID-19 Lockdown in India\n\nIs there any impact of COVID-19 lockdown (starting March 25, 2020) on air quality? Yes, it is! Choose a **city** and a station. By default, the chart shows ${html`NO₂, which is caused mostly by traffic (burning fossil fuels)`}.\n\n${html`Blue lines`} represent the data on and after March 24, 2020 and till lock down relaxations (May 4). ${html`Pinkish`} lines represent data on or after May 5.\n`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":663,"value":"viewof city = html``","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":195,"value":"viewof location = html``","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":116,"value":"$32","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":1023,"value":"$33","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":748,"value":"md`**Choose a different pollutant**:`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":441,"value":"viewof parameter = html`\n\n`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":826,"value":"md`### Credits\nData: [OpenAQ](https://openaq.org/), ${rawdata.meta.license}.\n`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":103,"value":"md`## Appendix`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":830,"value":"md`### Chart functions, helpers`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":375,"value":"function drawLines(svg) {\n svg.append('g').selectAll('path').data(nesteddata).join('path')\n .attr('d', d => line(d.values))\n .attr('fill', 'none')\n .attr('stroke', d => color(new Date(d.key)))\n .attr('stroke-width', .75)\n .attr('opacity', .5)\n .filter(d => valueOf(d.key) >= valueOf('2020-03-24'))\n //.attr('stroke', d => color(valueOf(d.key)))\n .attr('stroke-width', 1.2)\n .attr('opacity', 1)\n ;\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":869,"value":"function drawAqiLevels(svg) {\n svg.append('g').attr('transform', 'translate(' + (margin.left -5) + ', 0)')\n .selectAll('line').data(aqi.get(parameter)).join('line')\n .attr('y1', d => y(d.low))\n .attr('y2', d => y(d.high))\n .attr('stroke', d => d.color)\n .attr('fill', 'none')\n .attr('stroke-width', 10)\n \n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":167,"value":"line = d3.line()\n .x(d => x(d.date.valueOf() - d3.timeDay.floor(d.date).valueOf() - 5.5*hour))\n .y(d => y(d.value))\n .defined(d => d.value >= 0)\n .curve(d3.curveMonotoneX)\n \n;","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":109,"value":"height = 420","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":113,"value":"margin = ({top: 6, right: 0, bottom: 24, left: 45})","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":132,"value":"md`### Scales & Axes`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":106,"value":"x = d3.scaleTime()\n .domain([-5.5*hour, (24-5.5)*hour])\n .range([margin.left, width - margin.right])","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":126,"value":"y = d3.scaleLinear()\n .domain([0, d3.quantile(data.map(d => d.value).sort(d3.ascending), .99)])\n .range([height - margin.bottom, margin.top])\n .clamp(true)\n .nice()","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":325,"value":"color = d3.scaleTime()\n .domain([d3.min(data, d => d.date), new Date('2020-03-24'), new Date('2020-03-25'), new Date('2020-05-17'), new Date('2020-05-18'), new Date()])\n .range(['#999', '#999', 'deepskyblue', 'darkblue', 'hotpink', 'mediumvioletred'])\n .interpolate(d3.interpolateHcl)\n\n//d3.scaleSequential()\n //.domain([valueOf('2020-03-01'), valueOf(new Date())])\n //.interpolator(d3.interpolateBlues)","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":556,"value":"format = d3.format('-,d')","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":276,"value":"now = new Date()","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":352,"value":"hour = 60*60*1000","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":392,"value":"function valueOf(date) {\n return (new Date(date)).valueOf();\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":266,"value":"yyyymmdd = d3.timeFormat('%Y-%m-%d')","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":943,"value":"mmmdd = d3.timeFormat('%b %d')","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":8,"value":"md`## Data`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":1244,"value":"locations.get(+location)","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":206,"value":"date_from = '2018-10-01'","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":591,"value":"cities = (await d3.json('https://api.openaq.org/v2/cities?country=IN&limit=500&order_by=lastUpdated'))\n .results\n .sort((a, b) => d3.descending(a.count, b.count))","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":10,"value":"rawdata = d3.json(`https://api.openaq.org/v1/measurements?location=${location}&date_from=${date_from}&limit=10000¶meter=${parameter}`)","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":37,"value":"data = rawdata.results\n .filter(d => d.value > 0)\n .map(d => ({key: d.parameter, date: new Date(d.date.local), value: d.value}))","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":247,"value":"nesteddata = d3.nest()\n .key(d => yyyymmdd(d.date)).sortKeys(d3.ascending)\n .entries(data)","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":23,"value":"locations = new Map(\n (await d3.json(`https://api.openaq.org/v2/locations?country=IN&city=${city}`))\n .results\n .filter(location => valueOf(location.lastUpdated) > valueOf('2020-04-27'))\n .map(r => [r.id, r])\n )","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":1234,"value":"Array.from(locations.values()).filter(l => l.id == location)","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":438,"value":"parameters_all = (await d3.json('https://api.openaq.org/v2/parameters'))\n .results","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":1216,"value":"parameters = Array.from(locations.values()).filter(l => l.id == location)[0].parameters","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":852,"value":"$34","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":12,"value":"md`### Libraries`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":1224,"value":"d3 = require(\"d3@v5\")","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":950,"value":"import {legend} from \"@d3/color-legend\"","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"}],"files":"$W35","stdlib":"1"}} 31:"$30:body"