Air pollution in New Delhi hit extreme levels over the weekend and into Monday. India’s government has declared a public health emergency, shut down schools and halted construction projects. NEW DELHI — Air pollution in India’s capital climbed to poisonous extremes over the weekend and into Monday, blanketing streets in an opaque haze, delaying flights and prompting fights between politicians over who was to blame. Every winter, farmers in northern India burn crop stubble to make room for a new harvest. The fumes drift toward New Delhi and its suburbs, mixing with construction dust, vehicle emissions and smoke from fireworks displays during Diwali, the Hindu festival of light. A toxic cloud can linger for weeks, causing coughs, headaches and even highway pileups. This year, the pollution has become so dire that the Indian government declared a public health emergency on Friday, shutting all primary schools for days and halting […]