Doctors warn pre-Diwali cleaning can worsen asthma/allergies in Delhi’s pollution, as dust, mould and chemical fumes trigger coughing, wheezing and breathlessness. Delhi air pollution can worsen the health impact of pre-Diwali dust, mould and chemical fumes, doctors warn, especially for vulnerable residents. As Delhi faces poor air quality, medical experts are warning that intensive pre-Diwali cleaning can trigger severe respiratory issues, including asthma flare-ups and allergic reactions, due to.