There are Six main factors for air pollution in Delhi 1.     Wind direction 2.     Wind velocity 3.     Temperature 4.      Farm waste burning in Punjab 5.     Terrain of Delhi region 6.     Eco sphere   Generally during winter wind from direction largely from Northwest 65 to 75% days. Winds from Northwest carries smoke generated from burning or Agri-waste on large scale. Temperature in Punjab Haryana minutely low than Delhi it also one factor for air stream. Which contribute