Like everything else, there are fashions and trends in environment protection. Some of those things arise out of need. For example, a new situation arises and then a solution is found to deal with that situation. Then it becomes the trend for that time. But some of those solutions are forever.
They tackle a problem in a sustainable way and hence those solutions become popular. For example, saving water, reducing use of plastic, planting trees so on and so forth.
Similarly, a new trend is setting that will probably save the mankind in the long run. That is of Rain Water Harvesting. People all over the world are trying to save and use the rainwater instead of letting it go waste. It can really make a difference in the areas of water scarcity.
There are many innovative ways in which people are saving rainwater. There is a list of websites that will give you an idea of what one can do. Have a look at it and see if you can do any of it or add your innovation.