Data generated by CPCB of ambient air quality in various cities and towns of India under National Air Quality Monitoring Programme (NAMP) have been analyzed. A decreasing trends has been obseved in ambient sulphur dioxide levels in many cities like Delhi, Hyderabad, Kanpur, Lucknow, Mumbai etc. This may be due to various interventions like reduction of sulphur in diesel, use of CNG as the vehicular fuel in Delhi and Mumbai etc. No definite trend has been observed in ambient nitrogen dioxide and Respirable Suspended Particulate Matter, although various intervention have taken place to mitigate them.