New Delhi: Output of natural gas and fertiliser sectors -- two new segments included in the core infrastructure industries -- declined by 9.3 per cent and 1.3 per cent, respectively in April, 2011.

The government has included these two segments last month in the list of core infrastructure industries.

"This would help in capturing performance of economy in a better way," an official said.

Earlier, performance of six key sectors -- crude oil, petroleum refinery, cement, electricity, finished steel and coal -- was monitored by the Department of Industrial Policy and Promotion (DIPP) on a monthly basis.

With the additions, the weight of the core sectors has increased to 37.9 per cent from 26.7 per cent in the total Index of Industrial Production (IIP).

Natural gas and fertiliser production had registered a growth of 54.1 per cent and 7.8 per cent in April 2010 respectively.

The eight core infrastructure sectors grew by 4.6 per cent in April 2011 as against 8.5 per cent in the same period last year. During the 2010-11 fiscal, the eight key industries had expanded by 5.72 per cent, as against 6.64 per cent in the previous year.

Natural gas production registered a growth of 9.97 per cent during April-March 2010-11 compared to 44.59 per cent in the same period previous year. However fertiliser output during the period contracted by 0.02 per cent as against 12.69 per cent.

According to the data, coal and crude oil production grew by 2.8 per cent and 11 per cent respectively in April over the year ago period. Petroleum refinery output too grew by 6.6 per cent against 5.3 per cent in the same period previous year.

However, growth in steel and electricity production slowed to 4.8 per cent and 6.8 per cent from 12.9 per cent and 6.9 per cent respectively during the month. Cement output contracted by 1.1 per cent in April 2011 from a growth of 6.9 per cent in April 2010.