The World Environment Day falls on

World Environment Day is one of the United Nations' official international observance days — a fixed annual date, set by a UN General Assembly resolution, dedicated to raising global awareness and encouraging action on a specific issue; environmental protection is the theme reserved for this particular day.

The UN General Assembly created World Environment Day in 1972, immediately after the Stockholm Conference on the Human Environment, and the observance has been held every year since 1973 on 5 June — making 5th June the correct date.

• 16 September is the International Day for the Preservation of the Ozone Layer, marking the 1987 Montreal Protocol, not World Environment Day.

• 11 July is World Population Day, highlighting population-related concerns, not World Environment Day.

• 2 December is National Pollution Prevention Day in India, commemorating the Bhopal gas tragedy, not World Environment Day.

Hence, among the given options, 5th June is the date on which World Environment Day is celebrated.