New Delhi, Sept. 15 -- Policymakers in New Delhi and automakers across the country are currently focused on the same chart-a cartesian graph containing a single line. This is no straightforward line. Its slope will determine the production strategy for India's vehicle manufacturers for half a decade.

The graph will determine the next iteration of India's fuel efficiency rules, which were first introduced in 2017 to nudge manufacturers to reduce vehicle emissions. These rules, dubbed the Corporate Average Fuel Efficiency (Cafe) framework for cars and constant speed fuel consumption (CSFC) guidelines for trucks, are tightened every five years.

Discussions are ongoing for the third iteration of the Cafe rules and the second iteration of CS...