Answer:

Earth Day is an annual day on which events are held worldwide to increase awareness and appreciation of the Earth’s natural environment. Earth Day is now coordinated globally by the Earth Day Network, and is celebrated in more than 175 countries every year.

The name and concept of Earth Day was allegedly pioneered by John McConnell in 1969 at a UNESCO Conference in San Francisco.

Numerous communities celebrate Earth Week, an entire week of activities focused on environmental issues.

In 2009, the United Nations designated April 22 International Mother Earth Day. Earth Day is planned for April 22 (spring time) in all years at least through 2015.

In the spring time of 1970, Over 20 million people participated that year, and this Earth Day is now observed on April 22 each year by more than 500 million people and several national governments in 175 countries.

The name and concept of Earth Day was allegedly pioneered by John McConnell in 1969 at a UNESCO Conference in San Francisco. 
article taken from wikipedia.org