Air pollution impacting monsoon, India at a risk of losing 10-15% of mean rainfall in coming years: Experts

Vibha Sharma

Tribune News Service

New Delhi, August 23

While air pollution’s health and economic impacts are well established, experts say it is also impacting the Southwest Monsoon and the country is at a risk of losing 10%-15% of mean rains in coming years.

Places with highest levels of air pollution will see maximum impact with some seeing a reduction in rains by almost half of their average rainfall, they say. Besides a decline in precipitation due to anthropogenic (human-led) emitting sources in the atmosphere, the country might also see a surge in extreme weather events such as torrential rains, severe hailstorms or increasing number of dry days on account of rising air pollution, they add.

Air pollution is the result of suspended particles or aerosols in the atmosphere from anthropogenic sources along with natural dust. Monsoon, meanwhile, is a seasonal oceanic phenomenon governed by the change in the wind pattern due to differential heating of the tropics, driven by the temperature difference between land and ocean.

While increase in the concentration leads to warming of the atmosphere it also simultaneously cools land surface and according to meteorologists, any kind of change in differential heating of land and ocean will impact the wind pattern.

Dr Dilip Ganguly from the Centre for Atmospheric Sciences, IIT- Delhi, says air pollution is likely to decrease the Monsoon rainfall by 10%-15% for the entire country.

“Meanwhile, some places might even see reduced rains as high as 50%.

“Air pollution does not allow the landmass to warm up to the required levels. Due to the presence of pollutants, heating of land takes place at a slower rate. For instance, the required surface temperature is 40°C, while the presence of air pollution will result in restricting temperature up to 38°C or 39°C,” he adds.

Endorsing the views, Prof S N Tripathi from IIT-Kanpur and Steering Committee Member, National Clean Air Programme, said, “the most affected places would be the areas with more pollution levels”. 

“The Southwest Monsoon is driven by the difference between land temperatures and ocean temperatures. Presence of a large scale of aerosols over the Indian landmass would lead to dimming of the land surface. The entire process would lead to weakening of the dynamics of Monsoon, which might even include delay in onset of Monsoon,” he added.

Delhi gets its first smog tower

Delhi, one of the most polluted cities in the country, today got its first smog tower, a 20-metre-tall structure in Connaught Place to combat rising air pollution, to varying opinions with some calling it “a waste of money” and others a “necessity that will improve lives of citizens”.

It was inaugurated by Delhi CM Arvind Kejriwal.

Officials said the government will study the impact of smog tower on pollution and could add more such structures across the Capital.

Smog towers are structures designed to work as large-scale air purifiers and are fitted with multiple layers of air filters and fans to suck the air.

“This solution will hopefully reduce India’s urban air pollution thereby improving the lives of citizens. Large areas of cities can be covered if such smog towers are strategically placed at densely populated urban locations,” said Sandeep Navlakhe from Tata Projects Ltd, the makers of the tower.