Farm fires in summer
NEW DELHI: Delhi has seen more “poor” and “very poor” days than “moderate” or “satisfactory” days since March this year, as experts called for a year-round action plan to tackle air pollution in the city.
The Delhi government last month formulated a 14-point action plan to combat air pollution during summer.
Central Pollution Control Board (CPCB) data from March 1 to May 11 shows Delhi recorded a total of 55 “poor”, one “very poor”, 16 “moderate” and no “satisfactory” or “good” air quality days.
In comparison, there were 35 “poor” days and just three “very poor” days during the same period last year.
An air quality index (AQI) of 0-50 is termed “good”, 51-100 is “satisfactory”, 101-200 is “moderate”, 201-300 is “poor” and 301400 is “very poor”.
The last time Delhi recorded “satisfactory” day was when the AQI fell to 92 on February 27, as a result of rain across the city.
Between February 16 and May 10, Delhi’s average PM 2.5 concentration was 100 micrograms per cubic metre (µg/m3) -- 2.5 times higher than the national annual safe limit for PM 2.5 (40µg/m3) and 20 times the WHO limit of 5µg/m3 -- as per CPCB’S real-time data analysed by the Centre for Science and Environment (CSE). In comparison, the average PM 2.5 concentration last winter was 197µg/m3 (October 15 to February 15).
S.N Tripathi, a professor at IIT Kanpur and steering committee member of the National Clean Air Programme (NCAP), said dust has been a primary factor behind pollution, and attributed it to the absence rainfall, and other sources including emissions from coal power plants and farm fires which begun across Punjab and Haryana following the rabi harvest season.
“This indicates the need to once again identify sources and until that is done, immediate or long-term action cannot be taken. The primary problem for
Delhi has been re-suspended dust, but also dust particles transported from other states, particularly from Rajasthan. With power problems also common, coal-based power plants are running at a high capacity and the high PM 2.5 concentration over Delhi indicates combustion is a factor, which could be partially from farm fires and some localised burning, such as garbage burning or landfill fires,” he said, adding that there is a need for a one-year study of pollution sources.
Anumita Roychowdhury, executive director, research and advocacy, said that though pollution level is half the winter level, the PM 2.5 and PM 10 levels are still fairly high, especially considering that this is despite better meteorological conditions in summer.
“As the lower layer of the atmosphere is warmer and lighter in summer compared to winter, air can easily rise upwards and disperse pollution. The intensity of summer pollution is lower than winter and shows higher influence of dust but these levels are still beyond the safe limits and indicates the need for sustained action,” said Roychowdhury.
While crop burning has been a prominent source of pollution for Delhi in winters, largely occurring between October 15 and November 15, the rabi harvest season causes a similar action from farmers across Punjab and Haryana.
As per Nasa’s VIIRS satellite data, analysed by the Council on Energy, Environment and Water (CEEW), 14,957 farm fires have been reported in Punjab and 4,592 fires in Haryana between March 1 and May this year.
A Delhi Pollution Control Committee (DPCC) official said the Delhi government has launched a 14-point summer action plan from April 12 to focus on different sources of pollution, including anti-dust and anti-open burning campaigns. “The real-time source apportionment study for Delhi is also on track,” said the official.