Yes it's true. And then as a result of that:-
1. birds are easily audible and visible and they galloping in the sky with joy as no pollution is there;
2. Also trees are relaxed as lesser dust on their leaves, and also much fresher air for them making them play in sinc with nature;
3. Sky is too clean and that makes humans behold it dearly, such a sooth feeling!;
4. Animals are happy. They are not able to digest the fact that suddenly they are so relaxed and humans are not torturing them much!;
5. Soil is also relaxed as most of the industries are shut and hence lesser poison for it to digest ;
6. Stars and night sky is more beautiful as we have time to behold the sky;
7. Somehow common humans also are less interested in harming or hurting others as fear looms in the air (religion and caste ain't making much meaning now);
And, for me, personally, music is sweater, flute is dearer, mind is clearer, heart is working with better emotions, and Nature is at the door making me happy.
I just we were wiser as a race! Think of 7 billion sane and wise Humans and more Buddhas! Amin.