Growth of eight core sectors slowed down to 1.8 per cent in January due to fall in output of crude oil, refinery products and electricity, official data showed on Thursday.

Eight infrastructure sectors -- coal, crude oil, natural gas, refinery products, fertilisers, steel, cement and electricity -- had expanded by 6.2 per cent in January 2018.

Production of crude oil, refinery products and electricity contracted by 4.3 per cent, 2.6 per cent and 0.4 per cent, respectively, in January.

Growth rate of coal and cement sectors slowed to 1.7 per cent and 11 per cent in January as against 3.8 per cent and 19.6 per cent in January 2018, respectively.

However, natural gas, fertilisers and steel output grew by 6.2 per cent, 10.5 per cent and 8.2 per cent respectively during the month.

Sluggish infrastructure sector growth would also have impact on the Index of Industrial Production (IIP) as these segments account for about 41 per cent of the total factory output.

According to the Commerce and Industry Ministry data, during April-January 2018-19, the eight sectors recorded a growth rate of 4.5 per cent against 4.1 per cent in the same period of the previous fiscal.