Current Scenario

• In the Annual World Air Quality Report released by IQAir, a Swiss air quality technology company, India is ranked eighth among countries with the worst air quality index. 
• A total of 14 cities from North India occupy the list of 20 most polluted cities in the world.

Causes for increased Air pollution

• Climatic Conditions: Winter in the Indo-Gangetic Plains is characterized by cool temperatures and a shallow boundary layer, which reduces the vertical mixing of pollutants in the atmosphere. This stagnant air allows pollutants to accumulate near the surface, leading to higher concentrations.
• Temperature Inversion: During winter nights, temperature inversions are common, especially in low-lying areas. Inversion occurs when a layer of warm air traps cooler air near the surface, preventing the rise of pollutants. This trapped air mass can concentrate pollutants and contribute to the formation of smog.
• Burning of Crop Residue: After the rice and wheat harvests in the post-monsoon season, farmers in the region often burn crop residues in the fields to quickly clear the land for the next planting season. This agricultural practice, known as stubble burning, releases large amounts of particulate matter and pollutants into the air.
• Industrial Emissions: The Indo-Gangetic region is home to several densely populated cities with numerous industries. Increased energy consumption for heating purposes and industrial activities contribute to higher emissions of pollutants during the winter.
• Vehicle Emissions: Cold temperatures and stable atmospheric conditions can lead to the trapping of vehicle emissions, especially in urban areas with high vehicular traffic. This adds to the overall pollution load in the region.
• Construction Activities: Construction activities, which often involve the use of heavy machinery and dust-generating processes, contribute to the particulate matter in the air.
• Firecracker Use: During winter, festivals like Diwali involve widespread use of firecrackers, which release additional pollutants into the atmosphere.

Why in news?

• The entire Indo­Gangetic Plain witnesses a spike in air pollution every winter