Which one factor is responsible for the development of monsoon trough over northern plain?

The development of the monsoon trough over the northern plains is primarily influenced by the differential heating of land and sea. During the summer months, the intense heating of the Indian mainland creates a low-pressure area, while the cooler Indian ocean maintains higher pressure. This pressure difference leads to the formation of the monsoon trough, which is essentially a band of low pressure that attracts moisture-laden winds from the ocean, resulting in the southwest monsoon rains over the region.