The six core industries -- crude oil, petroleum refinery products, coal, electricity, cement and finished steel -- had expanded by 7.5 per cent in the year-ago period.
According to provisional data released today, production of cement declined by 1.1 per cent in April this year, as against a growth of 8.8 per cent in the same month of 2010.
Growth of finished steel production slowed down to 4.3 per cent during the month under review, compared to 12.9 per cent expansion in April last year.
In addition, electricity output grew by just 6.8 per cent in April this year, as against 6.9 per cent in the same month of 2010.
However, the other three sectors reported better growth during the month.
Crude oil production topped the table with growth of 11 per cent in April, compared to 5.1 per cent expansion in the corresponding year-ago period.
Petroleum refinery products registered a growth of 6.6 per cent in April, as against an increase of 5.3 per cent in the same month last year.
Coal output registered a growth of 2.9 per cent in April, 2011, a complete turnaround in comparison to the same month last year, when output had contracted by 2.9 per cent.
The slowdown comes a month after the six core infrastructure industries grew by 7.4 per cent in March, 2011.
During the 2010-11 fiscal, the sectors had expanded by 5.9 per cent, as against 5.5 per cent in the previous year.