Air pollution in Delhi continued to worsen, causing serious health concerns among residents even as weather officials warned of further worsening of air quality in the coming days. On 5 November, the levels of particulate matter PM10 and PM2.5 in the National Capital spiked to ‘hazardous’, leaving Delhiites gasping for breath. Particulate matter is a complex mixture that may contain soot, smoke, metals, nitrates, sulfates, dust, water and tire rubber. Fine particulate matter, also known as PM2.5, can enter the lungs and bloodstream. High levels of air pollution can cause a range of health problems, including respiratory ailments, cardiovascular diseases, adverse pregnancy outcomes and even death.