Bengaluru: Delhi has been witnessing very high levels of air pollution for consecutive days now but the parliament did not discuss the issue for the entirety of the Winter Session, from December 1 to 19. Meanwhile, the union government has claimed in parliament that there is no proof for any direct link between air pollution and ill health – this time, lung diseases. In a written reply on Thursday, December 18, the minister of state of the Ministry of Environment, Forest and Climate Change, Kirti Vardhan Singh said that there is “no conclusive data” to establish a “direct correlation between higher AQI levels and lung diseases”.No debate in parliamentThe Air Quality Index (AQI, a measure of air pollution that takes into account major pollutants in the atmosphere such as fine particulate matter) in Delhi at 4 pm on December 19 was 374, according to the daily bulletin by the Central Pollution Control Board. This marks the ninth consecutive day that air quality in the national capital has been in the “Very Poor” or “Severe” category this month. The AQI in the city on December 18 according to the CPCB was 373. This is the worst air quality that Delhi has witnessed in December since 2018, Hindustan Times had reported.The parliament was supposed to discuss the issue of air pollution in the Lok Sabha on Thursday. However, this did not happen and was pushed to the next day. It was not discussed on this day — the final day of the Parliament’s Winter Session, December 19 — either. Parliamentary affairs minister Kiren Rijiju blamed members of the opposition for ‘stalling’ the debate on air pollution, claiming that the Union government had been ready to discuss it.“…[T]he opposition’s behaviour during the debate in Lok Sabha on Viksit Bharat Guarantee for Rozgar and Ajeevika Mission (Gramin) (VB-G RAM G) Bill was unacceptable. Some of the opposition members even stood atop the desks of the table office and (Lok Sabha) Secretary General. Some Congress members also conveyed that there was no need for a debate on pollution. That is why the issue could not be taken up for discussion,” PTI quoted him as saying on Friday, December 19.No ‘conclusive data’A day before, on December 18, junior environment minister Kirti Vardhan Singh had said that said that there is “no conclusive data” to establish a “direct correlation between higher AQI levels and lung diseases”.Singh was responding to questions posed by Laxmikant Bajpayee, a Member of Parliament from the same party that Singh belongs to — the Bharatiya Janata Party. Bajpayee, an Ayurveda physician by training, had asked if the government “is aware that studies and medical tests have confirmed that due to prolonged hazardous AQI levels in Delhi/NCR, masses are developing lung fibrosis, an irreversible reduction in lung capacity”. He also asked whether the lung elasticity (the ability of lungs to expand while breathing) of citizens in the Delhi-NCR has drastically reduced to almost 50% as compared to lung elasticity of citizens living in cities having good AQI levels, and if the government proposes any solution to save the millions of the city’s residents from deadly diseases like pulmonary fibrosis, COPD, reduced lung function and continuously declining lung elasticity due to air pollution.Singh replied that while air pollution is one of the “triggering factors” for respiratory ailments and associated diseases, there is “no conclusive data which establishes a direct correlation between higher AQI levels and lung diseases”.Singh is wrong. Numerous scientific studies show a clear link between air pollution and lung diseases. And higher AQI levels reflect higher levels of pollution — a concept that the union environment ministry too relies on to issue advisories when pollution levels worsen. On December 13, for instance, an order of the Commission for Air Quality Management had advised children, the elderly and people with respiratory, cardiovascular, cerebrovascular or other chronic diseases to avoid outdoor activities and stay indoors “as much as possible”, and to wear masks if required to move outdoors — because Delhi’s AQI had reached 448 that evening, and was in the “Severe” category.Why Singh is wrongA 2025 study published in the journal Environmental Pollution analysed air quality data from two monitoring stations in Tamil Nadu across four years and screened 3,549 patients for respiratory illnesses. The researchers (from institutes including the National Institute of Research in Tuberculosis under the Indian Council of Medical Research — the apex body in India for the formulation, coordination and promotion of biomedical research) found a “strong correlation between pollution levels and respiratory diseases”. Another study published in Scientific Reports in 2023 found a “significant positive correlation” between high AQI levels in India and a higher rate of lung cancer (though it also found that factors such as smoking habits and occupational exposures may “obscure” this relationship). A study published this year analysed the relationship between respiratory diseases and air pollution across 27 countries including India over a four-year period (2018–2021). It found that overall, higher pollutant levels correlated with an increased number of COPD cases. “This aligns with known biological mechanisms where these pollutants exacerbate airway inflammation and chronic respiratory damage,” the study noted.Chronic obstructive pulmonary disease or COPD is a lung disease that causes restricted airflow and breathing problems. According to the World Health Organisation, smoking and air pollution are the most common causes of COPD, which is the fourth leading cause of death worldwide. It is incurable.Indian researchers are even trying to develop methods to predict lung disease severity based on the AQI. A study by Indian scientists that was presented at last year’s Asian Conference on Intelligent Technologies developed a way to predict air quality using image data and then assess lung disease severity based on AQI. Their models had very high testing accuracies (around 87% for AQI and 97% for lung disease severity), the preprint of their study shows.‘CAQM is working on this’ Singh in his response in Parliament on Thursday also said that the government has established the Commission for Air Quality Management (CAQM) under the Commission for Air Quality Management in NCR and Adjoining Areas Act, 2021 “for better coordination, research, identification and resolution of problems of air pollution” in the Delhi- NCR and adjoining areas. He added that the CAQM has been provided powers under the Act to take measures and issue directions to various agencies in the NCR and has been addressing the issue of air pollution in a “collective, collaborative and participative” way, involving all major stakeholders, Singh said. Currently, the CAQM has imposed Stage 4 of the Graded Action Response Plan, which are a series of progressively restrictive measures that the Delhi-NCR region has to implement with worsening AQI levels to curb dust, fumes and other sources of air pollution. Under Stage 4, measures include barring the entry of non-BS VI vehicles into Delhi, halting construction activity, and no fuel for vehicles without a PUC certificate. However, allegations of rampant, ongoing construction have surfaced during this time. On December 16, AAP leader Saurabh Bharadwaj had posted a video on social media to show that construction is still progressing unrestrained even within Delhi limits.GRAP 4 is bullshit !!Under the patronage of BJP’s high profile Minister, right under GRAP 4, construction going on throughout the night at Delhi Totally illegal construction in 2.5 acre farmhouse !!H-14 Pushpanjali farms, DelhiGuess the name of the Minister ?@MCD_Delhi pic.twitter.com/s6IIqq3ws1— Saurabh Bharadwaj (@Saurabh_MLAgk) December 16, 2025