{"id":83871,"date":"2026-01-23T11:29:59","date_gmt":"2026-01-23T05:59:59","guid":{"rendered":"https:\/\/vajiramandravi.com\/current-affairs\/?p=83871"},"modified":"2026-01-23T11:34:10","modified_gmt":"2026-01-23T06:04:10","slug":"delhi-winter-air-pollution","status":"publish","type":"post","link":"https:\/\/vajiramandravi.com\/current-affairs\/delhi-winter-air-pollution\/","title":{"rendered":"CAQM Report on Delhi Winter Air Pollution &#8211; Explained"},"content":{"rendered":"<h2 style=\"text-align: justify;\"><strong>Air Pollution Latest News<\/strong><\/h2>\n<ul style=\"text-align: justify;\">\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">A recent synthesis report by the <\/span><a href=\"https:\/\/vajiramandravi.com\/current-affairs\/commission-for-air-quality-management\/\" target=\"_blank\"><b>Commission for Air Quality Management<\/b><\/a><span style=\"font-weight: 400;\"> has identified secondary particulate matter as the single largest contributor to Delhi\u2019s winter air pollution.\u00a0<\/span><\/li>\n<\/ul>\n<h2 style=\"text-align: justify;\"><strong>Background: Understanding Delhi\u2019s Air Pollution Challenge<\/strong><\/h2>\n<ul style=\"text-align: justify;\">\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Delhi and the National Capital Region (NCR) experience severe air pollution every winter due to a combination of meteorological, geographical, and emission-related factors.\u00a0<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Low wind speeds, temperature inversion, and high moisture levels trap pollutants close to the ground, leading to persistent smog episodes.\u00a0<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Over the years, multiple studies have attempted to identify dominant pollution sources, but variations in methodology often led to conflicting conclusions, complicating policy responses.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">To address this gap, the Commission for Air Quality Management (CAQM) undertook a meta-analysis of existing scientific studies to present a consolidated and evidence-based assessment of pollution sources affecting Delhi during the winter months.<\/span><\/li>\n<\/ul>\n<h2 style=\"text-align: justify;\"><strong>Key Findings of the CAQM Meta-Analysis<\/strong><\/h2>\n<ul style=\"text-align: justify;\">\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">The CAQM synthesis report presents a clear source-wise contribution to winter air pollution in Delhi:<\/span>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"2\"><b>Secondary particulate matter<\/b><span style=\"font-weight: 400;\">: 27%<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"2\"><b>Transport emissions<\/b><span style=\"font-weight: 400;\">: 23%<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"2\"><b>Biomass burning<\/b><span style=\"font-weight: 400;\"> (including crop residue and municipal waste): 20%<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"2\"><b>Dust<\/b><span style=\"font-weight: 400;\"> (road and construction): 15%<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"2\"><b>Industrial emissions<\/b><span style=\"font-weight: 400;\">: 9%<\/span><\/li>\n<\/ul>\n<\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">The report clarifies that no new pollution sources have been identified.\u00a0<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Instead, it harmonises findings from earlier studies that used differing analytical techniques, thereby offering a unified scientific basis for policymaking.\u00a0<\/span><\/li>\n<\/ul>\n<h2 style=\"text-align: justify;\"><strong>Secondary Particulate Matter as the Dominant Pollutant<\/strong><\/h2>\n<ul style=\"text-align: justify;\">\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Secondary particulate matter is not emitted directly from sources such as vehicles or factories.\u00a0<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Instead, it forms in the atmosphere through chemical reactions involving primary pollutants like sulphur dioxide (SO\u2082), nitrogen oxides (NOx), and ammonia (NH\u2083).<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">These reactions lead to the formation of sulphates and nitrates, which together constitute nearly <\/span><b>25-60% of PM2.5 concentrations<\/b><span style=\"font-weight: 400;\"> during winter.\u00a0<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Fine particles of this nature are especially harmful as they penetrate deep into the lungs and bloodstream, aggravating respiratory, cardiovascular, and ophthalmic diseases.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">The CAQM report emphasises that focusing solely on visible emission sources may be insufficient without addressing these secondary chemical processes.<\/span><\/li>\n<\/ul>\n<h2 style=\"text-align: justify;\"><strong>Role of Ammonia in Pollution Formation<\/strong><\/h2>\n<ul style=\"text-align: justify;\">\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Ammonia plays a critical enabling role in the formation of secondary particulate matter.\u00a0<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Studies cited in the report indicate that nearly <\/span><b>80% of ammonia emissions in India originate from agricultural activities<\/b><span style=\"font-weight: 400;\">, particularly fertiliser use and livestock excreta.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">In the atmosphere, ammonia reacts with sulphuric and nitric acids, formed from SO\u2082 and NOx emissions, to produce ammonium sulphate and ammonium nitrate aerosols.\u00a0<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">These compounds significantly increase PM2.5 levels during winter, underscoring the rural-urban linkage in Delhi\u2019s air pollution problem.<\/span><\/li>\n<\/ul>\n<h2 style=\"text-align: justify;\"><strong>Transport, Biomass Burning, and Dust Contributions<\/strong><\/h2>\n<ul style=\"text-align: justify;\">\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Transport emissions remain the second-largest contributor, reflecting the high vehicle density, fossil fuel use, and congestion in Delhi-NCR.\u00a0<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Biomass burning, including crop residue burning in neighbouring States and municipal waste burning, contributes one-fifth of winter pollution, particularly during peak burning periods.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Dust pollution arises from unpaved roads, construction activities, and resuspension of settled particles.\u00a0<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Although often overlooked, dust contributes substantially to particulate load, especially under stagnant winter conditions.<\/span><\/li>\n<\/ul>\n<h2 style=\"text-align: justify;\"><strong>Policy Implications and Future Studies<\/strong><\/h2>\n<ul>\n<li style=\"font-weight: 400; text-align: justify;\" aria-level=\"1\"><span style=\"font-weight: 400;\">The CAQM report has important implications for air quality governance:<\/span>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"2\"><span style=\"font-weight: 400;\">It highlights the need for <\/span><b>multi-sectoral interventions<\/b><span style=\"font-weight: 400;\">, including agriculture, transport, energy, and waste management.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"2\"><span style=\"font-weight: 400;\">It calls for <\/span><b>integrated emission inventories<\/b><span style=\"font-weight: 400;\"> and updated source apportionment studies, with 2026 as the proposed base year.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"2\"><span style=\"font-weight: 400;\">The findings will support improved <\/span><b>Air Quality Early Warning Systems<\/b><span style=\"font-weight: 400;\"> and <\/span><b>Decision Support Systems<\/b><span style=\"font-weight: 400;\">, which had earlier faced limitations in forecasting pollution spikes accurately.<\/span><\/li>\n<\/ul>\n<\/li>\n<li style=\"font-weight: 400; text-align: justify;\" aria-level=\"1\"><span style=\"font-weight: 400;\">A more science-driven approach is expected to improve both preventive and responsive policy measures.<\/span><\/li>\n<\/ul>\n<p><b>Source:<\/b> <strong><a href=\"https:\/\/www.thehindu.com\/news\/national\/caqm-report-says-secondary-particulate-top-cause-of-delhi-winter-pollution\/article70538565.ece#:~:text=A%20synthesis%20of%20studies%20on,biomass%20burning%20at%2020%25%20including\" target=\"_blank\" rel=\"nofollow noopener\">TH<\/a><\/strong><\/p>\n","protected":false},"excerpt":{"rendered":"<p>The CAQM report highlights secondary particulate matter as the largest contributor to Delhi winter air pollution.<\/p>\n","protected":false},"author":21,"featured_media":83873,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[18],"tags":[3753,60,22,59],"class_list":{"0":"post-83871","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-upsc-mains-current-affairs","8":"tag-air-pollution","9":"tag-mains-articles","10":"tag-upsc-current-affairs","11":"tag-upsc-mains-current-affairs","12":"no-featured-image-padding"},"acf":[],"_links":{"self":[{"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/posts\/83871","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/users\/21"}],"replies":[{"embeddable":true,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/comments?post=83871"}],"version-history":[{"count":0,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/posts\/83871\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/media\/83873"}],"wp:attachment":[{"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/media?parent=83871"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/categories?post=83871"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/tags?post=83871"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}