You can say 'India is a country with a growing population' :)

davood007, The word 'population' has special meanings in science, but in general use the word 'population' has two basic meanings: 1-all the inhabitants of a particular place 2-the process of populating an area If you are talking about the population of India in the sense of 1)-- then population is a countable noun and requires the article "a". There are many populations around the world and there is a growing population in India. In that case as brother_dave stated, you should write in like this: India is a country with a growing population. If on the other hand you are talking about definition 2), then both of your choices are correct. India is a country with growing population. India is a country of growing population. When you are talking about 'population' as an activity or process it does not require an article since it is not a countable noun. It would also mean that some parts of India are not populated and that the process of population is growing as more and more areas of India become populated. Considering that India is already over-populated, this probably is not your meaning.

Both are right.