According to data from the Ministry of Earth Sciences, farm fires contributed up to 32 per cent of the tiny PM 2.5 lung-damaging pollutants in Delhi’s air – the highest in the past two years from mid-October to early November. PM 2.5 are fine particles that are 2.5 µm or less in diameter and can travel deep into the respiratory tract, reach the lungs and enter the bloodstream. Armaan Walia, 13, who suffers from asthma due to air pollution, said, “I find it difficult to breathe. I have asthma attacks. I think school should be online.”