Transport pollution in city drops to second lowest in country during lockdownUpdated: Mar 26, 2020 00:05 IST
Across 12 cities in India, Mumbai recorded the second lowest average nitrogen dioxide (NO2) levels on Sunday and also the second lowest particulate matter (PM2.5) concentration on Monday.
Sunday was the nationwide Janta Curfew which resulted in the lowest average level of transport pollution (NO2 pollution) ever recorded during March in India.
Restrictions on all major cities continued on Monday. The analysis — India’s coronavirus curfew resulted in the lowest one-day traffic pollution levels on record — was published by air pollution research group Centre for Research on Energy and Clean Air (CREA) on Wednesday.
Oxides of nitrogen are toxic gases that contribute to aerosol formation that can worsen respiratory conditions. They are formed from the burning of coal, oil, and emissions from vehicles and off-road equipment. “NO2 is responsible for an estimated 350,000 new cases of child asthma and 16,000 premature deaths per year in India,” the study said.
Chennai recorded the lowest NO2 levels at 4.8 micrograms per cubic metre (µg/m3) on Sunday and 5.2 µg/m3 on Monday, followed by Mumbai at 8.8 µg/m3 and 10.7 µg/m3 on Sunday and Monday against the safe limit of 80 µg/m3 for 24 hours.
According to the Maharashtra Pollution Control Board, the average NO2 levels in Mumbai range between 40-45 µg/m3 with all active sources.
Meanwhile, Patna was the most polluted among 12 cities for NO2 at 48.5 µg/m3 on Sunday and 47 µg/m3 on Monday followed by Ghaziabad at 31.4 µg/m3 and 35.8 µg/m3. Delhi recorded 28.7 µg/m3 and 28.6 µg/m3 during this period and was third most polluted of the 12 cities.
“Mumbai witnessed a sharp dip in NO2 and PM2.5 on Sunday and Monday, which indicates the transport sector plays a critical role in worsening air quality along with industries and waste burning,” said Sunil Dahiya, analyst, CREA.
“As the economy turns a corner and the coronavirus crisis passes, Mumbai needs to shift from the high fossil fuel dependency to avoid pollution levels bouncing back. This can be done through clean-energy private and public transport and encouraging walking and cycling,” Dahiya said.
For PM2.5 - a breathable particulate matter of 2.5-micron size that can easily enter the lungs and cause ailments - Kolkata was least polluted at 17.5 µg/m3 and 22.3 µg/m3 on Sunday and Monday followed by Nagpur and Howrah, West Bengal. Mumbai was the fourth least polluted at 22.7 µg/m3 on Sunday and the second least polluted on Monday at 22.3 µg/m3. Ghaziabad, Patna, and Delhi had the highest PM2.5 concentration.
“Air pollution across cities can vary depending on weather conditions. Lockdowns under the Covid-19 crisis should not be seen as a silver lining for improving air quality but a chance for cities to understand their background levels when major sources are on hold,” said Dahiya. “Once this crisis is over, states need to address air pollution by enforcing stricter emission standards,” Dahiya said.