Delhi air still 'very poor', 'unaccounted sources' contribute most to pollution, Pg4.

Key Highlights:

• Delhi's air quality remained in the 'very poor' category on Wednesday with an AQI of 353.
• The "others" category, representing unaccounted sources, contributed the most to pollution at 36.06%.
• The transport sector was the second largest contributor to Delhi's pollution at 15.77%.
• Stubble burning contributed 1.62% to Delhi's PM2.5 load.

Detailed Insights:

• The Decision Support System (DSS) data indicates a shift in pollution source contributions since Diwali.
• The "others" category includes emissions from sources outside the DSS study radius, such as power plants and rural burning.
• Contributions from neighboring areas like Ghaziabad, Jhajjar, and Gautam Buddha Nagar accounted for nearly one-fifth of Delhi's pollution.
• Experts suggest that stubble burning is expected to increase due to northwesterly winds carrying emissions from Punjab and Haryana.
• An outdated emission inventory makes it difficult to take targeted actions against specific pollution sources.

Key Concepts Involved:

• Air Quality Index (AQI): A measure of air quality based on concentrations of various pollutants.
• PM2.5: Fine particulate matter with a diameter of 2.5 micrometers or less, a major air pollutant.
• Stubble Burning: The practice of setting fire to crop residue after harvest.