which made Delhi one of the fastest-growing cities in the world. Dwarka Sub City, Asia's largest planned residential area, is located within the National Capital Territory of Delhi. Urban expansion has resulted in Delhi's urban area now being considered as extending beyond the NCT boundaries to incorporate the towns and cities of neighbouring states including Faridabad and Gurgaon in Haryana, and Ghaziabad and Noida in Uttar Pradesh, the total population of which is estimated by the United Nations to be over 28 million. According to the UN this makes Delhi urban area the world's second-largest urban area after Tokyo, although Demographia declares the Jakarta urban area to be the second-largest. The 2011 census provided two figures for urban area population: 16,314,838 within the NCT boundary, and 21,753,486 for the Extended Urban Area. The 2021 regional plan released by the Government of India renamed the Extended Urban Area from Delhi Metropolitan Area (DMA) as defined by the 2001 plan, to Central National Capital Region (CNCR). Around 49% of the population of Delhi lives in slums and unauthorized colonies without any civic amenities. The majority of these slums have inadequate provisions to the basic facilities and according to a DUSIB report, almost 22% of the people do open defecation. Hinduism is Delhi's predominant religious faith, with 81.68% of Delhi's population, followed by Islam (12.86%), Sikhism (3.40%), Jainism (0.99%), Christianity (0.87%), and Buddhism (0.11%). Other minority religions include Zoroastrianism, Baháʼísm and Judaism. According to the 50th report of the commissioner for linguistic minorities in India, which was submitted in 2014, Hindi is Delhi's most spoken language, with 80.94% speakers, followed by Punjabi (7.14%), Urdu (6.31%) and Bengali (1.50%). 4.11% of Delhites speak other languages. Hindi is also the official language of Delhi while Urdu and Punjabi have been declared as additional official languages. Culture Delhi's culture has been influenced by its lengthy history and historic association as the capital of India. Although a strong Punjabi Influence can be seen in language, Dress and Cuisine brought by the large number of refugees who came following the partition in 1947 the recent migration from other parts of India has made it a melting pot. This is exemplified by many significant monuments in the city. The Archaeological Survey of India recognises 1,200 heritage buildings and 175 monuments as national heritage sites. In the Old City, the Mughals and the Turkic rulers constructed several architecturally significant buildings,