Delhi is very polluted. We are thinking of getting some plants for home. my mother wants beautiful and big flowering(with big flowers) plants. However, I couldn't find any flowering plants that also cleans the air. Any suggestions would be helpful. Thanks!
A quite extensive list of "air cleaning" plants can be found in the NASA Clean Air Study.
Taking your desire for (large) flowers into account, you should consider
Now keep in mind that they have different filter properties so you should do some research which pollutants you want to reduce (some green, non-flowering plants may provide stronger "filter power"). The general recommendation is at least one fully grown plant per 100 square feet. Healthy plants filter way more than weak and struggling plants. Their cleansing power can drop to nearly zero. So keep them in good health, fulfill their needs with regards to water, light and nutrition and they will pay you back with flowers and somewhat cleaner air.