The foundation of the new city was laid Dec 15, 1911 - three days after the
coronation durbar. The capital was named New Delhi in 1927 and was formally
inaugurated Feb 13, 1931. The biggest change that the grand coronation durbar of Dec 12, 1911 brought in
to the city "was the decline of the old city of Shahjahanabad".
http://ummid.com/news/2011/December/13.12.2011/capitals_centenary.htm
http://ummid.com/news/2011/December/13.12.2011/capitals_centenary.htm