In today's parlance if somebody can understand the meaning of environment, it is everything. That means whatever we do, affects our environment. So, before doing anything, ask yourself a Q, what will be the impact on environment of my this action, is it necessary, is there a better alternative. After getting these answers consciously, go ahead.
Now environment means- air, water, land, jungles, all leaving beings.
All these can be elaborated further. Like whatever fossil fuels we are burning, we are releasing more and more carbonic gases to the atmosphere, thereby depleting ozone layer, increasing global warming, inviting more diseases etc etc.
We are using water as freely available commodity, without giving much/concrete action and polluting whatever is available at a jet speed. Today there are more sales of Water purifiers than much earlier. Just imagine you without water.
Land is being spoiled by polluted water and solid waste disposal. 50 years back there was no term like solid waste management, because many of the thing were recycled and reused like 'to my last drop of blood'.
Jungles are being cut at a compounding speed than growth, leave aside planting new ones. Thus we are reducing our oxygen bank, like we are reducing our bank balance after retirement. So ultimately------Death. Be ready for that, because still no action is being taken at any level, only talks, conferences and budgets are done