The findings of the study, conducted by the Tata Institute of Social Sciences last year, are contrary to the Raj Thackeray-led Maharashtra Navnirman Sena's rhetoric that Mumbai is being flooded with migrants.

Data from censuses conducted between 1961 and 2001 has been used as part of the study. "Natural increase, like the balance of births over deaths, added to the population more than migration," says D P Singh, from the Institutes Centre of Research Methodology.

The study points out that of the total migrants, the proportion from within Maharashtra dropped steeply to 16 per cent from 27 per cent in the 40-year period, while the proportion of migrants from other states saw a mild drop, from 34 per cent to 26 per cent.

Proportion of migrants from Gujarat has also dropped while that of migrants coming from four southern states has not changed much.

However, the proportion of migrants from the northern states -Uttar Pradesh, Bihar, Rajasthan and Madhya Pradesh-has risen, the study said. The proportion of migrants to Mumbai from within Maharashtra is the highest at 37 per cent.