Over 7,000 buses, a majority from neighbouring states, were booked for flouting pollution norms in the national capital in the last six years, the Delhi government informed the state Assembly. The highest number of buses, 3,328, that were challaned for the lack of valid PUC certificates, came from Uttar Pradesh, followed by 2,064 from Rajasthan. The number of buses registered in Delhi that were challaned for violating pollution norms, was 643, during the period. According to the minister, action against buses causing pollution picked up manifold in last one year. A total of 5,086 buses were challaned for lacking valid PUC certificates, from 2017-till February this year. The number was quite low in the previous years – 244 in 2012-13, 216 in 2013-14, 506 in 2014-15, 189 in 2015-16,.and 978 in 2016-17, he said in a written reply. The enforcement wing of the Transport Department carries out regular checks of pollution standards of the buses coming to Delhi from neighbouring states. Buses not having valid PUC certificates are challaned, the minister said. The fine for not having a valid PUC is Rs 1,000. The State Transport Authority of Delhi has no power to cancel permits of buses from other states violating norms in the city under the Motor Vehicle Act, 1988. The Transport Department corresponds with their counterparts in other states in case offending buses belong to government undertakings. As per a joint agreement among states sharing the National Capital Region (NCR), it is mandatory that buses entering Delhi are run on CNG.