Few of the reasons which lead to increased pollution in Delhi are-

  1. Ever growing population of Delhi
  2. Construction of houses at the cost of Green Patches.
  3. Unstoppable construction activities in the city both by Public Works Department as well as individuals
  4. Industries operating in the city
  5. Burning of garbage
  6. Large number of vehicles on the roads of Delhi
  7. Climate of Delhi is another factor as on a normal day the air flow in Delhi is 1 metre per second. But in order to end air pollution the speed of air should be 6-10 metre  per second                        
  8. Garbage is dumped haphazardly and burnt indiscriminately. 
  9. Public roads are used for parking causing congestion. 
  10. Burning of stubble is also an important factor. 

All this combined together has led to increase in pollution nodes around Delhi and neighbouring areas.