Delhi has been experiencing phenomenal growth of population since 1951 recording decennial growth rate of 52.44%, 52.91%, 52.98%, 51.45% and 47.03% during 1951-61, 1961-71, 1971-81, 1981-91 and 1991-01 decades respectively. One of the main causes for this spurt in the growth of population is migration into the city not only from the adjacent states but also from others such as Bihar.