One theory is that the city was planned by the Mughal emperor Shah Jahan in the 17th century. Shah Jahan was a great builder and is credited with constructing many of the most famous buildings in Delhi, including the Red Fort and the Jama Masjid.
Another theory is that the city was planned by the British architect Edwin Lutyens in the early 20th century. Lutyens was responsible for designing many of the government buildings in Delhi, including the Rashtrapati Bhavan and the Secretariat Building.
It is also possible that the city was planned by a combination of architects and builders over a long period of time. Delhi has been an important city for centuries and has been home to many different cultures and civilizations. It is likely that the city's architecture reflects the contributions of many different people over time.