India's cougar couples: When a man loves an older woman

Article 19 of our constitution gives us right to freedom but subject to certain restrictions. Enjoiment of those right should not creat nuisance and havoc in the enjoyment of others.Religion, Caste ,Creed , Language ,Customs or Culture etc. do not stop a man or woman  to marry the opposite s*x but subject to certain restriction. Enjoy your life in the manner you like.Culture and life is changing rapidly. Try to move with the versatile world / Society but rule of law isabove all. 

Which law says that to get married a man should be older than a woman? which law renders  the marriage of an older woman with a younger man void or illegal?