The first conference on human environment was held in ____________.

• The Joined together Countries Conference on the Human Environment was the primary UN summit on the environment. 
• It was to be put on 5 June 1972 in the Swedish capital Stockholm. This conference focussed on the administration of the earth's common assets, contamination, and instructive and social viewpoints on the environment. 
• UNEP, or the United Nations environment program, was organised as a result of this conference.
• This conference is about the environmental issues that the world was facing at that time or will face in the future.

Hence, the correct answer is option A.