In line with its climate-change commitments and domestic pollution concerns, India has one of the world’s largest programmes to expand renewables–a tripling of capacity over the next five years.

But after two years of record expansion, the diversion of a national clean-energy cess to subsidise GST (goods and services tax)-induced losses and a new import duty to protect domestic manufacturers of solar equipment threaten to derail India’s ambitious 2022 target. This is why February 1, 2018–the day the ruling Bharatiya Janata Party (BJP) will present its last ...