Earth Day is being celebrated on the 22nd day of April every year. Essentially, it is the anniversary of the start of the Modern Environmental Movement, which happened in 1970.
During that time, Americans could not care less about the environment, as they emit more and more gas emissions. In fact, they had embraced the smell of air pollution, comparing it to prosperity. All of this, then, led to their awakening to environmental issues.
On April 22, 1970, people have gained consciousness as they put environmental concerns at the forefront of their minds.