The eight core industries -- fertilisers, cement, steel, electricity, crude oil, coal, petroleum refinery products and natural gas -- have a combined weight of about 38 per cent in the Index of Industrial Production (IIP).
Core sector growth was 2.4 per cent during the April-January period of this financial year compared with 6.9 per cent in the same period of 2012-13.
Coal output contracted 0.7 per cent in January. Petroleum refinery production registered a fall of 4.5 per cent and natural gas output shrank 5.2 per cent.
Steel output growth slowed to 3.4 per cent, while the expansion in cement production eased to 1.5 per cent. Crude oil registered a growth of 3 per cent and electricity generation expanded 5.7 per cent.