Cow belt
The Cow Belt is a cultural region of India that extends over the Hindi-speaking states of Bihar, Madhya Pradesh, Rajasthan, Jharkhand, Chhattisgarh, and Uttar Pradesh. The name comes from the high reverence given to cows, which are considered sacred in the Hindu religion. This area is predominantly rural and Hindu, hence why cows are highly respected in this region, due to both economic value and religious beliefs. Cultural and political dominance
Cow belt refers to the most of Uttar Pradesh and Bihar that consists of the vast Ganges plain, an area of flatness, which often floods dramatically during the monsoon. These states have been most dominant states in Indian politics and culture since independence. This is partly because these are also the most populous states of the country and partly because the region plays a central role in the religious landscape of the Hindus. The Ganges River which forms the backbone of the state, is the sacred river of Hinduism and two of Hinduism's most holy towns are in the state, namely Varanasi and Prayagraj, which is also one of the venues of the Kumbh Mela. See also 
Hindi Belt
Cattle slaughter in India
Standard of living in India
States of India by size of economy

References 

Politics of India
Regions of India
Economy of India by state or union territory
Belt regions