New Delhi, June 30 -- The ministry of road transport and highways (MoRTH) is working on strengthening the Pollution Under Control (PUC) certification system in the run up to the winter pollution season in Delhi-NCR, additional secretary Mahmood Ahmed said on Monday. The changes under consideration, he said, include geo-tagging of vehicles at testing centres, end-to-end encryption of emissions data, mandatory insertion of the testing probe into the vehicle tailpipes and eliminating manual entry of emissions data to curb manipulation. The ministry is also redesigning testing equipment and considering stricter enforcement measures, particularly in Delhi-NCR. Acknowledging that "there are a lot of gaps in the way the PUC regime is being run acr...