India hosted world environment day in 2018 most recently.

Explanation:
India has hosted World Environment Day two times.

The most recent time India hosted World Environment Day was in 2018, with the theme “Beat Plastic Pollution“. The event was held on June 5th, 2018, and was hosted by the Indian government in partnership with the United Nations Environment Programme (UNEP).

Previously India also hosted World Environment Day in 2011 with the theme “Forests: Nature at your Service“. Both times, it was hosted in Delhi, the capital of India.