Delhi is the most polluted city in the world and according to one estimate, air pollution causes the death of about 10,500 people in Delhi every year. During 2013–14, peak levels of fine particulate matter (PM) in Delhi increased by about 44%, primarily due to high vehicular and industrial emissions, construction work and crop burning in adjoining states. Delhi has the highest level of the airborne particulate matter, PM2.5 considered most harmful to health, with 153 micrograms. Rising air pollution level has significantly increased lung-related ailments (especially asthma and lung cancer) among Delhi's children and women. The dense smog in Delhi during winter season results in major air and rail traffic disruptions every year. According to Indian meteorologists, the average maximum temperature in Delhi during winters has declined notably since 1998 due to rising air pollution.