Led by crude oil and finished steel, the output of the six core infrastructure industries grew by 7.4 per cent in March, 2011, an improvement from the 6.8 per cent expansion clocked a year ago.

For the 2010-11 fiscal, the key infrastructure sectors - with a weight of 26.7 per cent in the overall Index of Industrial Production (IIP) -- expanded by 5.9 per cent, as against 5.5 per cent in the previous year.

According to provisional data released today, crude oil production topped the table with growth of 12.1 per cent in March, compared to 3.5 per cent expansion in the corresponding year-ago period.

Petroleum refinery products registered a growth of 8.5 per cent in March, a complete turnaround in comparison to the same month last year, when output had contracted by 1.1 per cent.

Growth in electricity and cement production slowed down marginally in the reporting period to 7.6 per cent and 6.5 per cent, respectively, from 7.9 per cent and 7.8 per cent in the previous year.

Finished steel production also showed an improvement from 7.7 per cent to 9.9 per cent in March.

However, in stark contrast, coal output contracted by 1.2 per cent in March, 2011, compared to 8 per cent expansion in the corresponding year-ago period.