India’s aluminium producers are drawing expensive power from the national grid and adding to pressure on utilities with low coal stock, the Aluminium Association of India, or AAI said on Tuesday, as state-run Coal India has curbed supplies.

A crippling shortage across the country has pushed state-run Coal India to impose temporary supply curbs to non-power consumers, including the energy-intensive aluminium industry, pushing producers to draw electricity from the grid.

Indian aluminium producers such as Hindalco Industries Ltd and Vedanta Ltd largely use power generated from the so-called captive utilities – which are not connected to the national grid – where the companies generate electricity for self-use.

AAI estimates aluminium production to annually account for 5-6 percent of India’s total power demand met through the national grid.

“Since we are going to the (national) grid, that increases power demand in the country and puts further pressure on coal plants which already have low fuel,” AAI said in a statement.

Electricity use in India’s eastern Odisha state, which accounts for over half of India’s aluminium smelting capacity, rose 25 percent during the first half of October, government data showed, growing over five times faster than national average.