The environment is an important issue to a great many people, and any time that someone makes a political or lifestyle decision in the modern day, there is always an environmental question to answer.
Certainly, it comes into play with mobile phones, as when thrown away they can be a major environmental hazard, with many of their components taking more than a century to degrade.
One major response to this has been the development of organizations who pay for old mobile phones so as to recycle the phone or its components.
Even if your phone is very old and no longer really any use as a phone, it will have components which are usable, and even if the amount that you get for it is not much, it is better than nothing.
Of course, many mobile phone companies and stores have a similar policy of paying for old mobile phones or using them as a part-exchange component allowing the customer to make a saving on the new cell phone they wish to buy.
In doing this, they prevent people from simply throwing away an old phone when they cease to have a use for it.
If the environment is a source of concern to you, then the options available for disposal of your old mobile phone have never been greater.
There is of course always a push on to find more environmentally friendly ways of manufacturing, and it is to be hoped that these methods will develop quickly.