Describe the key points of the revised Global Air Quality Guidelines (AQGs) recently released by the World Health Organisation (WHO). How are these different from its last update in 2005? What changes in India's National Clean Air Programme are required to achieve these revised standards?

Covers only one regional source-control measure you can suggest for meeting stricter air standards; it has nothing on the WHO guidelines themselves.

• Crop residue burning is estimated to contribute up to 35% of pollutants in Delhi-NCR's winter air.
• Draft CAQM rules of 16 September 2026 keep a 'red entry' on land records for 15 months, with compensation of ₹5,000 to ₹30,000 by landholding.
• Farm fires in Punjab are falling, with 2025 recording the lowest count of 5,114, and CAQM has directed districts to set up 'Parali Protection Forces'.

For the third part, cite the gap between India's standards and WHO's 2021 guideline, and the NCAP changes needed to close it.

• India's annual NAAQS limit for PM2.5 is 40 µg/m³, far looser than WHO's 2021 guideline of 5 µg/m³; NAAQS were last revised in 2009.
• Critics note NCAP measures progress mainly by PM10, not the finer and more harmful PM2.5, and has no statutory backing or penalty for failure.
• Reforms suggested: give NCAP legal backing with city-specific targets, shift the headline metric to PM2.5 and health outcomes, and plan by airshed like the Commission for Air Quality Management.

Use it as an example of the source-specific, seasonal controls India relies on to cut particulate peaks, the kind of action any tightening of clean air goals will need.

• In Arjun Gopal v. Union of India (2018), the Supreme Court allowed only green and reduced-emission crackers, banned joined crackers, barium salts and online sales, and limited Deepavali bursting to 8 p.m. to 10 p.m.
• In October 2025 the Court allowed green crackers in Delhi-NCR only from 18 to 21 October, at fixed hours, with QR codes for traceability.
• On 30 September 2026 the Bench signalled it may allow CSIR-NEERI's next-generation joined green crackers with conditions on noise, shell size and number, and bursting intervals; the CPCB barium report is awaited.

Use it to show the gap between WHO's 2021 PM2.5 guideline and Indian standards and actual Delhi levels, and to argue NCAP must track particulates, not just the composite AQI.

• WHO's 2021 guidelines set annual PM2.5 at 5 µg/m³, far below India's standard of 40; Delhi's average PM2.5 from 1 January to 28 September 2026 was 69 µg/m³, unchanged from 2025.
• Delhi's September 2026 AQI of 102 was a five-year low, yet CPCB data cited by The Indian Express show PM2.5 rose from 35 to 39 µg/m³ and PM10 from 104 to 106 µg/m³.
• Since overall AQI is the worst sub-index of eight pollutants, NCAP should track PM2.5 and PM10 city by city, publish pollutant-wise trends and use source apportionment.