Delhi's air quality was at the season's worst as a combined effect of smoke from stubble burning and moisture turned the city into a "gas chamber" leaving people gasping and prompting authorities to announce closure of primary schools and a four-fold hike in parking fees among a series of sweeping measures. As a thick blanket of haze hung low over the city, visibility levels plunged, affecting flight and train operations. It permeated living rooms and even the underground metro stations in the city making it difficult to breathe, turning eyes watery and producing burning sensation. The Indian Medical Association said the capital was witnessing a "public health emergency" and appealed to the government to stop outdoor sports and other such activities in schools to protect the health of children.