BENGALURU: The air quality over Bengaluru has improved sharply, with air pollutants cut by more than half in April, when the lockdown was in force, according to an analysis of air pollution data by NGO Greenpeace.

The NGO analysed Central Pollution Control Board data on nitrogen dioxide (NO2) and PM 2.5 levels in three South Indian cities — Bengaluru, Chennai and Hyderabad — and compared data of April 2020 with that of April 2019. 

Both nitrogen dioxide (released due to burning of fuel) and PM 2.5 (particulate matter of a certain size) are harmful to the respiratory system. The analysis found that NO2 levels reduced by more than half in Hyderabad and Bengaluru. “NO2 is the main source of nitrate aerosols, which form an important fraction of PM 2.5.

The major sources of anthropogenic emissions of NO2 are combustion processes such as power generation, vehicles, and industrial activities. NO2  has harmful effects on the lungs,”the NGO said in a statement. Although the lockdown had reduced air pollution, “tackling one crisis can’t be done at the expense of another”, said Avinash Chanchal, climate campaigner at Greenpeace India. “It is time that all non-attainment cities are included under the National Clean Air Programme immediately and its strict implementation is ensured to address long-term air pollution.”