The service sector in India has recorded its slowest growth in about 18 months during the month of April as companies faced higher costs of raw materials, petrol and labour, according to a latest business survey.

The HSBC Services Purchasing Managers' Index, which is indicated or the overall service sector in the country, fell to 50.7 during April, which its lowest level since October of 2011. The same index was recorded at the level of 51.4 in March. A rating of more than 50 shows expansion while a rating of below 50 shows contraction.

This data showed that the April became the third straight month of falling growth in the sector, which makes up about 60 per cent of the entire Indian economy and a slowdown in the service sector could significantly affect the overall economic growth. The HSBC India Composite Output Index fell to 50.5 in April compared to 51.4 in March. Business Activity Index declined to 50.7 in April from 51.4 in the previous month.

"The latest reading indicated that activity increased marginally and at the slowest pace since October 2011," it said. The index was calculated following a survey of 400 firms in the country.