NEW DELHI: What India’s metros are breathing may have a link with rising acute respiratory illness (ARI) cases hospitals are logging. There were 2 lakh ARI cases in Delhi during 2022-24, with thousands needing hospitalisation — a surge the health ministry Tuesday linked to rising air pollution, while noting that the causal pathways remain complex. Responding to a question by Dr Vikramjit Singh Sahney in RS, junior health minister Prataprao Jadhav said polluted air is a “triggering factor” for respiratory diseases, and worsening air quality in urban centres is being closely monitored through an expanding national surveillance system.Govt data shows that Delhi’s six central hospitals together reported 67,054 ARI emergency cases in 2022, 69,293 in 2023, and 68,411 in 2024, with admissions rising from 9,878 to 10,819 over the same period. Similar spikes were seen in Chennai and Mumbai, where thousands sought emergency care for breathing difficulties during severe pollution episodes. According to the Health Ministry, the impact of polluted air is shaped by multiple factors — including food habits, occupation, socio-economic conditions, immunity and medical history — making some people far more vulnerable than others.To capture these patterns in real time, the National Centre for Disease Control (NCDC) now operates over 230 sentinel surveillance sites across 30 States and UTs. Digital ARI surveillance was also launched in August 2023 through the Integrated Health Information Portal.