Monks and nuns in ancient times, especially in regions where Buddhism and Jainism flourished, followed a practice known as "Vassa" or "Varsha." Vassa refers to the three-month monsoon retreat during the rainy season, and it is observed by Buddhist monks and nuns. During this period, they temporarily settle in one place to avoid disturbing nature and to focus on meditation and study.

Monks and nuns typically take shelter in monasteries or viharas during the Vassa. These monastic residences are designed to provide a suitable environment for meditation, study, and communal living. Monasteries often have individual living quarters for monks or nuns, common areas for communal activities, and meditation halls. The monastic community comes together to support each other in their spiritual practices.

The tradition of observing Vassa is not only found in Buddhism but also in Jainism, where it is known as "Chaturmas." Jain monks and nuns follow a similar practice of staying in one place during the rainy season, engaging in intensive spiritual activities.

The idea behind taking shelter during the rainy season is rooted in the principle of non-violence (ahimsa) and compassion for all living beings. During the monsoon, there is a higher risk of unintentionally harming insects and other small creatures when traveling through wet and muddy areas. By staying in one place, monks and nuns reduce their environmental impact and focus on their spiritual pursuits.