Nowadays, many people have their own cars and frequently use itthem , which is clarified by itstheir convenience and comfortable
Cars - they, their, them / car -it, its
Although, by driving cars, people has given rise to many serious consequences.
...this sentence needs improvement with its presentation.
However, usage of too many cars has given rise to many seriuos issues.It is undeniable fact that the unlimited use of cars is responsible for the range of problems that influence our lives negatively
....you have been telling this repeatedly. Here you need to start discussing what those negative reasons are.