‘Good air in March rare in Delhi’

NEW DELHI: As India remained under lockdown for the fourth consecutive day, the nation’s focus stayed on preventing the spread of Covid-19 infections and helping stranded citizens. Meanwhile, an unprecedented change was in the air, literally. With steep decline in traffic volumes, construction and industrial activity, India on Saturday recorded the best air quality in years, if not decades.The day’s average air quality index was in the top category (“good”) in as many as 35 cities out of 101 monitored by the Central Pollution Control Board on Saturday. Experts are calling this “unprecedented” and “unbelievable”, not seen since the national air quality index was launched in 2014.Delhi recorded its bestever AQI of 45 on Saturday, a day after a spell of rain. This was the first “good air” day in the capital since August 18 last year and only the third in more than three years. This was also the first time that the capital recorded AQI in the “good” range outside the monsoon months.A clear blue sky in the capital, with pollution levels downAn average AQI of 45 has never been achieved in Delhi since the air quality index was launched. March is a month of weather transition. An AQI in the ‘good’ range is unheard of in Delhi during this month,” said Dipankar Saha, former head of CPCB’s air lab.Improvement in air quality was seen across Indian cities, a trend clearly linked to the national lockdown. TOI studied AQI data of eight major cities during the past 14 days and found significant reduction in air pollution in all cities in the seven days since Sunday’s janata curfew. Additionally, an overwhelming number of CPCB stations across India, 108 out of 116, reported cleaner air on March 26 — Day 2 of the lockdown — as compared to the same day last year.“It is unbelievable. I would say 35 cities reporting good air quality in a single day has not happened since the AQI regime was started. That this is taking place in March is even more remarkable,” said A B Akolkar, former member secretary, CPCB.While weather too plays a crucial role in regulating air pollution levels, the sharp improvement in air quality across the country is clearly due to reduced vehicular movement and other industrial activities, the experts said. Exactly how much impact the reduction in activities is having on air quality will need to be studied.“This is a great opportunity to study the role of various sources on pollution. Most source apportionment studies in the past have stated that roughly 70% of air pollution over cities such as Delhi is contributed by human activities. That such activities are down to a record low at the moment gives a window to researchers to study their impact,” Saha said.(With inputs from Atul Thakur)