In today's world as we know pollution is a very big nuisance for all. What I am proposing is a molecular sieves air filter that reduces NOx and other harmful chemical substances coming out of the exhaust pipes of vehicles. Using this filter allows for better combustion characteristics and less harmful exhaust. These can be cheaply be produced and they can be regenerated after every 4 to 5 months. So it can be reused and on regeneration they become as good as new. Using this filter can drastically reduce pollution and even pollution from heavy duty CI engines can be significantly reduced. Doing extensive test on it, it was be found it to be performing very well without a great deal effect on the engine. Diesel engines use EGR technology to reduce emissions but EGR greatly reduces the efficiency of the engine. Whereas molecular sieves air filter do a better job without such downsides. This will help to take steps towards cutting the rate of emissions from tailpipes of vehicles and preserve the environment.