Can betel leaf (paan) be grown outside its traditional regions and in greenhouses?

Betel leaf needs warm temperatures, high humidity and shade, and it cannot take frost or very dry heat, which is why it is traditionally grown in the boroj that creates a controlled humid shaded micro climate. Because the crop already relies on a built structure, it can be grown in new areas if you can recreate those conditions, and some growers do use polyhouse or net house setups to manage shade and humidity, especially in cooler or drier regions. The catch is the higher cost and the skill needed to manage humidity and disease in an enclosed space, where rot can spread fast. So it is realistic to grow outside the classic belt, but treat it as a protected cultivation project with proper structure, a market for the leaves, and disease management planned. Confirm feasibility for your climate with your horticulture department.