Relevance: GS-3 (Environment & Ecology, Pollution Control)  |Source: The Indian Express

1. What is the Core Issue?

Recent data shows that Delhi’s air pollution profile is changing.

• The Shift: Direct smoke and dust are slowly reducing, but a new, highly dangerous and invisible gas called Ground-level Ozone is rising sharply.
• The Spread: Pollution is no longer just a “Delhi problem.” Surrounding NCR cities like Noida, Ghaziabad, and Hapur are now recording worse air quality than the capital.

2. The Science: Understanding the Pollutants

To fix the problem, administrators must understand how these pollutants behave:

• Primary Pollutants: These are toxic gases and dust released directly into the air from vehicle exhaust pipes, factory chimneys, or burning wood. (Examples: PM2.5, Nitrogen Dioxide, Carbon Monoxide).
• Secondary Pollutants (The Ozone Threat): These are not directly emitted by any vehicle. Instead, they form in the air when vehicle smoke mixes with chemical fumes (VOCs) under strong summer sunlight.

3. The Good News: Policy Success

Why is direct smoke and dust (Primary Pollutants) decreasing?

• BS-VI Vehicles: The strict upgrade to BS-VI engines has successfully reduced toxic smoke from car exhausts.
• Ujjwala Yojana (PMUY): By providing clean LPG cylinders to poor households, the government has stopped the burning of firewood and coal in domestic kitchens.
• National Clean Air Programme (NCAP): A dedicated government mission that has successfully forced cities to reduce particulate dust.

4. The Bad News: Why is Ozone so Dangerous?

• It is a Summer Problem: While thick smog (PM2.5) chokes us in the winter, Ozone peaks during the extreme summer heat because it needs strong sunlight to form.
• The Invisible Killer: Unlike winter smog, ozone is invisible. However, breathing it acts like sunburn on the lungs, severely aggravating asthma.
• Threat to Food Security: Ozone is highly toxic to plants. It destroys plant leaves and stops photosynthesis, which severely reduces the harvest of vital crops like wheat and rice.

5. The Way Forward (Administrative Action)

Our old methods of fighting pollution need an upgrade:

• Summer Action Plans: Currently, our emergency pollution protocols (like GRAP) only activate in winter. We desperately need strict ‘Summer Action Plans’ to fight ozone on high-heat days.
• Targeting New Sources: Instead of just stopping dust, the government must regulate chemical factories, paint manufacturing, and petrol pumps that release the fumes needed to create ozone.
• ‘Airshed’ Management: Air does not respect city borders. Trying to clean Delhi while neighboring districts pollute is useless. The CAQM (Commission for Air Quality Management) must enforce a single, unified strategy across the entire National Capital Region.

UPSC Value Box

• Good vs. Bad Ozone: Ozone high up in the stratosphere is “Good” (it protects us from UV rays). However, Tropospheric (Ground-level) Ozone is “Bad” (it is a toxic pollutant).
• VOCs (Volatile Organic Compounds): Chemical fumes emitted from paints, solvents, and fuels that react with sunlight to create ground-level ozone.
• CAQM: A powerful statutory body created to manage pollution across the combined regional “airshed” of the NCR.

With reference to air pollution dynamics in India, consider the following statements:

1. Ground-level ozone is a primary pollutant directly emitted from the exhausts of diesel vehicles and thermal power plants.
2. While Particulate Matter (PM2.5) concentrations typically peak during the winter months, Ground-level Ozone levels generally peak during the summer.
3. The measurement of Ground-level Ozone is included under the National Ambient Air Quality Standards (NAAQS).

Which of the statements given above is/are correct? (a) 1 and 2 only (b) 2 and 3 only (c) 1 and 3 only (d) 1, 2 and 3

Correct Answer: (b)