With natural gas and cement showing decline in production, the growth of eight core infrastructure industries slowed down to 5.3 per cent in May against 7.4 per cent a year ago.
The core industries - crude oil, petroleum refinery products, natural gas, fertilisers, coal, electricity, cement and finished steel - have a weight of 37.90 per cent in the overall index of industrial production, according to the provisional data released on Thursday.
Read: Norms for infra debt fund cleared
With addition of two sectors - fertilisers and natural gas - the number of key infrastructure sectors, picked up separately for measuring performance has now gone to eight.
While six sectors showed positive growth, the pace of expansion declined in the case of refinery products and steel.
Natural gas and cement showed a negative growth of 9.6 per cent and 2.3 per cent, respectively.
However, sectors like crude oil, electricity, fertilisers and coal showed an improvement in growth.
During April-May 2011, these sectors grew at a lesser pace by 4.9 per cent compared to 7.9 per cent in the same period last year.