The eight industries - crude oil, petroleum refinery products, natural gas, fertilisers, coal, electricity, cement and finished steel - have a weightage of 37.9 per cent in the overall Index of Industrial Production (IIP).
During fiscal 2011-12, the core industries grew by 4.3 per cent compared to 6.6 per cent in 2010-11, according to the data released by the Commerce Ministry today.
Crude oil and natural gas production contracted by 2.9 per cent and 10.1 per cent in March, respectively. Crude oil production had grown by 12.1 per cent while natural gas output had declined by 10.6 per cent in March 2011.
Electricity, steel and fertiliser output slowed down by 2.1 per cent, 2.3 per cent and 1.5 per cent respectively, in the month under review compared to 7.6 per cent, 12 per cent and 3.9 per cent respectively in March 2011.
In February, the eight infrastructure industries grew by 6.8 per cent in February after a dismal performance of 0.5 per cent a month ago.
Petroleum refinery output too slowed down by 1.6 per cent compared to 8.5 per cent in March 2011.