What was the criteria of bifurcating Punjab and Bengal at the time of partition?

Religious majority

The partition of British India in 1947 resulted in the creation of two independent states, India and Pakistan. The criteria for bifurcating Punjab and Bengal were primarily based on religious majority, as the main driving force behind the partition was the desire to create separate nations for Hindus and Muslims.
The Muslim majority provinces of British India, Punjab and Bengal, had very large areas where the non-Muslims were in majority. Eventually it was decided that these two provinces would be bifurcated according to the religious majority at the district or even lower level.