Answer

Yes, Jains can generally use an underground metro.

Explanation

In Jain Dharma, using transportation is not forbidden by itself. A metro is a common public mode of travel, and using it for necessary purposes is normally acceptable.

What matters is:

• Intention should be proper
• Harm should be minimized
• One should avoid careless violence as much as possible

If a person is observing stricter vows or doing special tapasya, they may choose simpler travel according to their discipline.

Spiritual Understanding

Jain ethics focuses on reducing harm in daily life. The use of a metro does not itself break Jain principles, as long as one remains mindful, disciplined, and respectful of ahimsa.

Takeaway

A Jain may use an underground metro in ordinary life. The key is mindfulness, necessity, and minimizing harm.