In Jain cosmology, people in Mahāvideh Kṣetra are described as being very tall, strong, and long-lived because that region is a highly auspicious and balanced area compared to Bharat and Airavat Kṣetra.

The main reasons are:

1. Punya karma is greater there

Souls born in Mahāvideh generally have much more auspicious karma, so their bodies are naturally superior.

1. Best balance of time and environment

Mahāvideh is not in the same declining spiritual condition as Bharat Kṣetra. Its conditions are more stable and refined, so the physical body is also finer and larger.

1. Body shape follows karma in Jainism

In Jain philosophy, the body is not random. Its height, lifespan, beauty, strength, and all features are determined by karma.

1. It is a land where Tirthankars are available

Mahāvideh is especially blessed because Tirthankars are born there continuously in many parts, so the whole region is considered spiritually elevated.

So, in short: people are tall in Mahāvideh because of superior karmic merit and the auspicious nature of that kshetra.

If you want, I can also explain how Mahāvideh differs from Bharat Kṣetra in Jain cosmology.