GS Paper III

News Excerpt:

A new study has revealed that a rare and unusual ‘triple-dip’ La Nina event, influenced by climate change, significantly impacted the air quality in different regions of India in the winter season of 2022-23.

About the news:

• The results showed that the air quality worsened in cities across peninsular India, such as Mumbai, Coimbatore, Bengaluru, and Chennai, in the winter season of 2022-23
• The southern region witnessed an increase in the levels of fine particulate matter (PM 2.5), which can cause respiratory and cardiovascular diseases.
• In contrast, the air quality improved in northern India, such as Ghaziabad, Rohtak, Noida, and Delhi, in the same period.
• This is the first time that air quality in Indian cities has been linked to a La Nina event and indirectly to climate change, which is making El Nino and La Nina more severe.
• The study was conducted by researchers at the Bengaluru-based National Institute of Advanced Studies and the Pune-based Indian Institute of Tropical Meteorology(IITM).
• IITM was established in 1962 at Pune as a distinct unit of the India Meteorological Department (IMD) on the recommendation of the World Meteorological Organisation (WMO).
• Currently, IITM is under the administrative control of the Ministry of Earth Sciences (MoES).

Usual pollution pattern in winter in India:

• Usually, from October to January, northern Indian cities, particularly Delhi, experience very high concentrations of PM 2.5.
• Various meteorological factors such as temperature, moisture, heaviness in the air, wind speed and direction play a role in trapping pollutants in the lower levels of the atmosphere. 
• During this season, fine particulate matter from farm fires (stubble burning) in neighbouring regions (Haryana, Punjab and Western UP) increases levels of pollutants in the city amidst a decrease in wind speeds.
• The western and southern parts of the country have always had relatively lower pollution levels because of their proximity to oceans.
• The winter of 2022 showed a significant deviation from this normal.

Reasons for the anomaly in pollution during winter of 2022:

• The most crucial factor in explaining the anomaly of winter 2022 was a change in the normal wind direction.
• During this time, the wind usually blows in the northwesterly direction, for example, from Punjab towards Delhi and further into the Gangetic plains. 
• This is one of the main reasons why agricultural waste pollutants in Punjab and Haryana flow into Delhi.
• In the winter of 2022, however, the wind circulation was in the north-south direction. 
• The pollutants being carried from Punjab and Haryana bypassed Delhi and surrounding areas and flew over Rajasthan and Gujarat to southern regions.

Conclusion:

Climate change-induced changes in wind patterns could significantly impact local air pollution distribution, necessitating a long-term plan to reduce human-caused emissions at their source. This approach would benefit air quality and climate change efforts, creating a win-win scenario.