In Jain tradition, not eating green vegetables on Aatham (Ashtami/Atham) is a form of ahiṃsā and discipline.

Significance:

• Green vegetables are believed to contain more living beings and are considered more harmful to consume.
• On Aatham, many Jains observe restraint in food to reduce violence in daily life.
• It helps in tapasya (austerity), self-control, and detachment from taste.
• Such observance is also a way to purify thoughts, speech, and conduct.
• It supports the Jain ideal of minimum harm to all जीवs.

So, the main purpose is not just a rule, but a spiritual practice of non-violence and discipline.

If followed with श्रद्धा and sincerity, it becomes a step toward inner purification and karma reduction.