An estimated 2,40,000 Indian immigrants are among 11.5 million foreigners living illegally in the United States without proper immigration documents, according to latest official figures.

The flow of Indians coming clandestinely to the U.S. has, in fact, doubled between 2000 and 2011, said the latest report by the U.S. Department of Homeland Security.

During the same period the total number of illegal foreign immigrants increased from 8.46 million to 11.51 million.

India with 2,40,000 illegal immigrants ranks seventh in the list which is topped by Mexico with 6.8 million followed by El Salvador (6,60,000), Guatemala (5,20,000) and Honduras (3,80,000).

China is placed fifth in the list, but tops among the Asian countries with 280,000 illegal immigrants, followed by Philippines (270,000) which is ranked overall sixth.

India is followed by 230,000 illegal immigrants from Korea, Ecuador (210,000) and Vietnam (170,000).

The Cuban-born population living in the US was excluded from the estimates since, according to immigration law, most Cubans are admitted or paroled into the US and are eligible a year later to apply to adjust to legal permanent residency (LPR) status.

Of the 11.5 million unauthorised immigrants in 2011, 1.6 million (14 per cent) entered the US on January 1, 2005 or later. Larger numbers came during 2000-2004 (3.3 million or 29 per cent) and 1995-1999 (3.0 million or 26 per cent).

Fewer came between 1990-1994 (1.6 million or 14 per cent) or in the 1980s (1.9 million or 17 per cent), the Department of Homeland Security said in its report.

An estimated 8.9 million (77 per cent) of the total 11.5 million unauthorized immigrants living in the US in 2011 were from North America, including Canada, Mexico, the Caribbean, and Central America.

The next leading regions of origin were Asia (1.3 million) and South America (0.8 million).

Between 2000 and 2011, the greatest increase in the unauthorized population occurred among natives of North America (2.8 million), the report said.

Mexico continued to be the leading source country of unauthorized immigration to the United States. There were 6.8 million unauthorized immigrants from Mexico in 2011, representing 59 per cent of the unauthorized population.

From 2000 to 2011, the Mexican—born unauthorized population increased by 2.1 million or an annual average of 190,000.

California remained the leading state of residence of the unauthorized immigrant population in 2011, with 2.8 million.

The next leading state was Texas with 1.8 million unauthorized residents, followed by Florida (740,000), New York (630,000) and Illinois (550,000).

The 10 leading states represented 73 per cent of the unauthorized population in 2011.

In 2011, 59 per cent of unauthorized immigrants were ages 25 to 44 years, and 53 per cent were male.

Males accounted for 57 per cent of the unauthorized population in the 18 to 34 age group in 2011 while females accounted for 57 per cent of the 45 and older age groups.