Relevance: GS-3 (Environment, Pollution)

Source: The Hindu, ISRO Studies

Why in the News?

Recent satellite-based assessments show that India’s actual emissions—especially methane (CH₄) and nitrous oxide / nitrogen dioxide (NO₂)—are  significantly higher than officially reported estimates.
Satellite observations indicate:

• 10–15% higher methane concentrations over major agricultural belts
• 20–30% higher NO₂ levels over industrial clusters

What the Satellite Data Reveals

1. Invisible / Unaccounted Sources

• Small brick kilns
• Dispersed rice-paddy fields
• Informal livestock units
• Bio-waste and residue burning

These sources remain poorly captured in traditional ground-based emission inventories.

2. Spatial Hotspots Identified

• Indo-Gangetic Plain: Persistent methane plumes
• Chhattisgarh & Odisha: High aerosol optical depth over thermal power regions
• Night-time fire radiance data: Far more stubble-burning events than reported by States

3. Consequences

• Worsening air quality and public health impacts
• Distorted national climate inventories
• Weakened mitigation planning and policy design

Way Forward

• Integrate satellite datasets into national emissions reporting systems
• Strengthen State-level monitoring and verification mechanisms
• Formalise inventories for small, dispersed emission sources

UPSC Prelims Value Box

• Aerosol Optical Depth (AOD): Measures how much sunlight airborne particles block; higher AOD indicates higher particulate pollution.
• Institution: ISRO’s National Atmospheric Research Laboratory conducts satellite-based atmospheric monitoring.
• Policy Link: National Clean Air Programme (NCAP) targets a 40% reduction in PM2.5 and PM10 by 2026.

Prelims Practice Question

Q. With reference to emissions monitoring in India, consider the following statements:

1. Satellite-based measurements can detect methane and nitrogen oxides even from scattered agricultural and informal industrial sources.
2. India’s official emission inventory is entirely satellite-based as mandated under the National Clean Air Programme.
3. Aerosol Optical Depth is used to estimate particulate pollution loads.

How many of the above statements are correct?

A. One only
B. Two only
C. All three
D. None

Correct Answer: B. Two only

Statement 1 and 3 are correct. Statement 2 is incorrect as India’s emission inventories are not entirely satellite-based under NCAP.

One Line Wrap: Satellite evidence shows India’s real emissions exceed reported levels, highlighting the need for satellite-integrated pollution governance.