Dhaka, April 14 -- Nepal's Kathmandu has been covered by a toxic haze of dust and smoke for multiple days, with the sun glowing an eerie red through the smog. The Himalayan nation is famous for its mountains, including Mount Everest, but its capital is located in a valley which hasn't seen significant rainfall in six months. Widespread forest fires in the valley's vicinity - particularly in the southern and eastern regions - have sent air pollution levels spiking, along with vehicle emissions and stagnant air trapped by the city's unique topography."Kathmandu Valley is shaped like a bowl. When there is no rainfall, pollutants remain suspended in the air without settling, and there is little wind movement. As a result, pollution accumulate...