What could be the reason of uneven distribution of population in India?

Rugged terrain and unfavourable climatic conditions are primarily responsible for sparse population in Jammu and Kashmir, Uttarakhand, Rajasthan etc. Their population density is less than 250. Assam and most of the Peninsular states have moderate population densities. Hilly, dissected and rocky nature of the terrain, moderate to low rainfall, shallow and less fertile soils have influenced population densities in these areas. The Northern plains and Kerala in the south have high to very high population densities because of the flat plains with fertile soils and abundant rainfall.