Hari Singh, 58, and Mukul Sahni, 25, are truck drivers over three decades apart in age, but bound by a fascination for a new document that's part of the centre's GST regime - the E-way bill. The new system, introduced in April this year, requires the use of this electronically generated number to be carried in person by truckers. It helps the government to track the movement of goods by trucks. The government has also pitched it as an anti-evasion measure, compared to the earlier system of paper documents that was more prone to corruption.