Section 115D(2)(a) in The Central Motor Vehicles Rules, 1989
(a)the vehicle intended for retro-fitment complies with following conditions, namely:-(i)it conforms to Bharat Stage-II or subsequent emission norms;(ii)it belongs to category M & N with Gross Vehicle Weight exceeding 3500 kg.;(iii)it was not retrofitted earlier;(iv)it is not provided with permits for carrying dangerous or hazardous good, as defined in Central Motor Vehicle Rules, 1989;