The correct answer to this open question is the following.
Although there is no further context or specific references we can say the following.
The environmental personal mission could be the following.
To preserve the natural resources and raw materials provided by nature, assuming the responsibility that this conveys that results in the protection of the flora and fauna in nature.
The four reasons why I think having it may enhance responsible living in your environment are the following.
1.- It will clearly define the expectations about the protection of the environment.
2.- It will create the kind of consciousness in people to take care of nature.
3.- It will indicate that this is a priority for the members of the community.
4.- It will establish the purpose to show respect and honor mother nature that provides us the food, water, and other non-renewable resources to survive on the planet.
Major industries around the world do not have any respect or consideration for taking care of nature. These industries were only interested in big profits no matter what. They produced their goods and polluted the air, polluted the water, and also contributed to noise pollution.
These industries never considered that raw materials and natural resources are limited, and one day, humans are going to suffer if we as citizens of the world do not put a stop to these large corporations.
That is why our mission is very important.