not harmful to the environment
eco-friendly cars make a low impact on the environment.

to keep something safe from harm, damage, or loss
You should protect your brother from bullies.

the process of making land, water, air, etc., dirty and not safe or suitable to use
Air pollution from traffic fumes is a serious problem in large cities.

existing in nature and not produced or caused by people
Cotton is a natural material unlike plastic.

capable of producing desired results without wasting materials, time, or energy
My car is very efficient. I rarely have to buy gas.

an effect or influence
Divorce can have a negative impact on young children.

to lift up
Too much salt in your diet can elevate your blood pressure.

to remove or take away
People are trying to reduce or eliminate unhealthy foods from their diet.

to support or encourage
The government is promoting the use of public transportation instead of driving.

involving the use of natural products and energy in a way that does not harm the Environment
Solar power is sustainable energy because it will always be available, while oil is not because supplies may be depleted.

the careful use of natural resources (such as trees, oil, and water) to prevent them from being lost or wasted
Water conservation practices include recycling and reusing water.