Different authorities and sources define North India differently.
States under Northern India Zonal Council in orange
Government of India definitions
The Northern Zonal Council is one of the advisory councils, created in 1956 by the States Reorganisation Act to foster interstate cooperation under the Ministry of Home Affairs, which included the states of Chandigarh, Delhi, Haryana, Himachal Pradesh, Jammu and Kashmir, Punjab and Rajasthan.
The Ministry of Culture established the North Culture Zone in Patiala, Punjab on 23 March 1985. It differs from the North Zonal Council in its inclusion of Uttarakhand and the omission of Delhi.
In contrast, the Geological Survey of India (part of the Ministry of Mines) included Uttar Pradesh and Delhi in its Northern Region, but excluded Rajasthan and Chandigarh, with a regional headquarters in Lucknow.
Indian press definition
The Hindu newspaper puts Bihar, Delhi and Uttar Pradesh related articles on its North pages. Articles in the Indian press have included the states of Bihar, Gujarat, Madhya Pradesh, and West Bengal in North India as well.
The Tropic of Cancer, which divides the temperate zone from the tropical zone in the Northern Hemisphere, runs through India, and could theoretically be regarded as a geographical dividing line in the country. Indian states that are entirely above the Tropic of Cancer are Jammu and Kashmir, Himachal Pradesh, Punjab, Haryana, Delhi, Uttarakhand, Uttar Pradesh and Bihar and most of North East Indian states. However that definition would also include major parts of Rajasthan, Madhya Pradesh, Jharkhand and West Bengal and minor regions of Chhattisgarh and Gujarat.
In Mumbai, the term "North Indian" is sometimes used to describe migrants from eastern Uttar Pradesh and Bihar, often using the term bhaiya (which literally means 'elder brother') along with it in a derogatory sense, however these very people are not considered North Indian by the inhabitants of Punjab, Himachal Pradesh, Uttarakhand, Haryana and Rajasthan. In Punjab, people from the same region (Uttar Pradesh and Bihar) are often referred to as Purabias, or Easterners. The Government of Bihar official site places the state in the eastern part of India. Within Uttar Pradesh itself, "the cultural divide between the east and the west is considerable, with the purabiyas (easterners) often being clubbed with Biharis in the perception of the westerners."