The correct answer is option 4: Protection of plants.

Van Mahotsav is an annual tree planting festival in India. It is celebrated during the first week of July as a way to promote and create awareness about the importance of trees and forests. During this festival, people engage in activities such as planting trees, organizing tree plantation drives, and distributing saplings to individuals and communities. The aim is to protect and conserve plants and their habitats, as forests play a crucial role in maintaining ecological balance, mitigating climate change, and providing various ecosystem services. Through Van Mahotsav, the focus is on the preservation and sustainability of plants and forests, rather than cutting down or increasing crop production as mentioned in the other options.