I am from india. taking the covid vaccine doesn't 100% ensure that the person will not get covid again, if he/she doesn't follow the covid rules. right? may be everyone on earth have to wear the mask this year also. correct?

Some thoughts: Covid 19 will likely be with us indefinitely. A fully vaccinated population would still leave some venerable to the disease & as agents of spread. There are conflicting data whether many masks do anything more than act as a signal that wearers are willing to try to reduce spread. Yet treatments, yet poorly reported on, have reduced morbidity in the worst cases. There is reason for hope.

COVID 19: Yes, the vaccine does not provide 100% guaranteed infection against infection. Do recommend continued use of an appropriate mask and social distancing even after vaccinated.

COVID vaccine: If not otherwise contraindicated, if you have access to the available COVID 19 vaccination, it is recommended. It will provide a level of protection against the infection. Continue to wear the mask to protect others.