Delhi, officially known as the National Capital Territory of Delhi, is a city and a union territory of India containing New Delhi, the capital of India. It is bordered by the state of Haryana on three sides and by Uttar Pradesh to the east. The NCT covers an area of 1,484 square kilometers. According to the 2011 census, Delhi's city proper population was over 11 million, the second-highest in India after Mumbai, while the whole NCT's population was about 16.8 million. Delhi's urban area is now considered to extend beyond the NCT boundaries, and include the neighboring satellite cities of Ghaziabad, Faridabad, Gurgaon and Noida in an area called the National Capital Region and had an estimated 2016 population of over 26 million people, making it the world's second-largest urban area according to the United Nations. Recent estimates of the metro economy of its urban area have ranked Delhi either the most or second-most productive metro area of India. Delhi is the second-wealthiest city in India after Mumbai and is home to 18 billionaires and 23,000 millionaires. Delhi ranks fifth among the Indian states and union territories in human development index. Delhi has the second-highest GDP per capita in India. Delhi is of great historical significance as an important commercial, transport, and cultural hub, as well as the political center of India.
Delhi features a dry-winter humid subtropical climate bordering a hot semi-arid. The warm season lasts from 21 March to 15 June with an average daily high temperature above 39 °C. The hottest day of the year is 22 May, with an average high of 40 °C and low of 28 °C. The cold season lasts from 26 November to 9 February with an average daily high temperature below 20 °C. The coldest day of the year is 4 January, with an average low of 2 °C and high of 14 °C. In early March, the wind direction changes from north-westerly to south-westerly. From April to October the weather is hot. The monsoon arrives at the end of June, along with an increase in humidity.
Private schools in Delhi, which use either English or Hindi as the language of instruction are affiliated to one of three administering bodies, the Council for the Indian School Certificate Examinations (CISCE), the Central Board for Secondary Education (CBSE) or the National Institute of Open Schooling (NIOS). In 2004–05, approximately 1,529,000 students were enrolled in primary schools, 822,000 in middle schools and 669,000 in secondary schools across Delhi. Female students represented 49% of the total enrolment. The same year, the Delhi government spent between 1.58% and 1.95% of its gross state domestic product on education.
According to Euromonitor International, Delhi ranked as 28th-most visited city in the world and first in India by foreign visitors in 2015. There are numerous tourist attractions in Delhi, both historic and modern. The three UNESCO World Heritage Sites in Delhi, Qutb Complex, Red Fort and Humayun's Tomb are among the finest examples of Indo-Islamic architecture. Another prominent landmark of Delhi is India Gate, a 1931 built war memorial to soldiers of British Indian Army who died during First World War. Delhi has several famous places of worship of various religions. One of the largest Hindu temple complexes in the world, Akshardham is a major tourist attraction in the city. Other famous religious sites include Lal Mandir, Laxminarayan Temple, Gurudwara Bangla Sahib, Lotus Temple, Jama Masjid and ISKCON Temple.
Delhi is also a hub for shopping of all kinds. Connaught Place, Chandni Chowk, Sarojini Nagar, Khan Market and Dilli Haat are some of the major retail markets in Delhi. Major shopping malls include Select Citywalk, Pacific Mall, DLF Promenade, DLF Emporio, Metro Walk and Ansal Plaza.