Delhi pollution worsens as authorities impose Stage II measures

Delhi’s air quality deteriorated sharply ahead of Diwali, prompting authorities to implement Stage II pollution-control measures as crop fires and stagnant weather added to concerns across the northern plains. Pakistan’s Punjab recorded substantially more satellite fire detections than India’s Punjab in October, but the counts do not establish how much smoke, if any, reached Delhi or contributed to its pollution. Delhi’s Central Pollution Control Board (CPCB) readings entered the very poor category on November 2. The city’s average AQI was around 330 on November 3, and at least three monitoring stations recorded levels above 400, classified as severe. The CPCB defines an AQI of 301 to 400 as very poor and 401 to 500 as severe. The figures reflect different readings at particular times and through different measurement systems. Early on November 3, IQAir recorded Delhi’s AQI at 215, while the CPCB reported 332. IQAir and the CPCB use different scales and methods. Delhi’s AQI had been 60 on October 30 after rainfall, and the city’s average for October was 167, its cleanest October in more than eight years, according to the reporting. Under Stage II of the Graded Response Action...