Great work represented and you have mentioned the things which contributes to pollution.
Yes, you are right about the big cities like Delhi as you mentioned it has air pollution which creates respiratory problems; in our country this is also a big problem in big cities like Karachi and Lahore which includes very much industries and it also contributes in air pollution which should be stopped.

I never throw waste outside on streets or roads, in-fact I keep them in my bag and throw it when I see a dustbin

I am very delighted about this step of yours, I also does the same but I use my pockets in place of bag and also guide children to the same by keeping environment clean.
Best of luck for the contest