At present, there are a total 326 Government-approved computerised checking centres for petrol and CNG vehicles at different petrol pumps and workshops and another 169 such checking centres for diesel vehicles which issue the certificates around the city, which is valid for three months to one year. The fee is Rs35 for two-wheelers, Rs45 for four-wheelers running on petrol and Rs60 for all diesel vehicles. There are 75 lakh vehicles in the national Capital. About 10 lakh vehicles coming into the Capital from NCR towns like Gurgaon, Noida, Ghaziabad and Faridabad are a major area of concern as there is virtually no pollution testing in these cities.