Which city is known as the City of Prime Ministers?

Allahabad is known as the City of Prime Ministers because seven out of 15 prime ministers of India since independence have connections to Allahabad(Jawaharlal Nehru, Lal Bahadur Shastri, Indira Gandhi, Rajiv Gandhi, Gulzarilal Nanda, Vishwanath Pratap Singh and Chandra Shekhar).