Proportion of ethanol in petrol may dip to 15% from current 20%. (EPA Images pic)MUMBAI: India's drive to replace imported oil with home-grown biofuel faces a setback as the lowest monsoon rainfall in more than a decade hits corn and sugarcane crops, forcing New Delhi to prioritise food security over ethanol production.

The proportion of ethanol in Indian petrol is poised to fall below the official 20% target in the supply year that began this month, industry insiders say, reversing gains made after the government achieved the milestone some five years ahead of schedule.

A sustained drop in ethanol use would undermine one of Prime Minister Narendra Modi's signature energy-security programmes and leave India more reliant on overseas crude at a volatile time for energy prices amid persistent geopolitical uncertainty.