Kolkata is one of the most polluted cities of the world. The city has been plagued by one of the most prominent pollution problems of the of the world, the air pollution. The time period of 2000-2008 saw a huge number of vehicles hitting Kolkata’s streets, which has lead to a significant increase in air pollution. Realising this, the Supreme Court has decided to impose a ban on the vehicles, which are more than 15-year old. The ban was imposed finally on 1 st August, 2009. It was thought that this ban would result in substantial reduction of pollution, but the reduction in SPM, RPM, SOX and NOX could not be achieved to the desired level. A statistical analysis through bar diagrams, box-plots and ANOVA was performed to compare the different type of pollutants to determine whether the ban on the old vehicles was effective or not.