Ganga is a river. I didn't mention the Ganga anywhere. Are you talking about the Indian civilization?
If so...oh boy, I can't believe that I need to repeat all this. I posted a long post some time back in response to a Pakistani "think tank" member, and I was astonished somebody would actually ask such a question. It's like asking what Americans have contributed to science or technology in the 20th century. I suppose there is an active force in Pakistani education that deliberately teaches that India hasn't contributed anything to human culture. I can think of no other explanation for this bizzare question.
https://defence.pk/threads/who-is-an-indian.409661/page-11#post-8038464
Anyway:
1) Literature: Vyasa, Kalidasa, Bhasa, Shakuntalam, Raguvamsham, and all the other classics of ancient literature? Shudraka, Asvagosha, and so on and so on? Heck, just mentioning the names of great works and great poets would fill a page - and that's just the ancients.
Now the great South Indian ones? Sangham literature of Tamil Nadu itself is more richer and amazing in breadth than those of entire civilizations.
Or the works of medeival India, both Hindu and Islamic? Or even Jain and Buddhist? Ramacharitamanasa?
Seriously, I can't even begin to simply name all the literary movements and traditions...just use google and learn a bit, it will only take you 10 years to scratch the surface.
2) Dance: From Natyashastra, the classic philosophical study on dance, and the great dance forms it has produced and continues to produce? Bharatanatyam to Kootiyattam to Kathak to Kathakali to...again, please do read up on the great dance forms and traditions of India, from ancient to modern.
3) Music? Oh boy. From Carnatic to Hindustani, from Tansen to Tyagaraja, from...
4) Architecture? The Shilpakala of Dravidian culture, the majestic temples and structures from the Chola period, the Buddist stupas, Kalinga arcitecture, the intricacies of Tanjavur, and so on and on?
5) Philosophy? Sorry boss, too tired to even list out India's contributions.
Mind you, I haven't even attempted to mention the literary and artistic accomplishments of each region - Malayalam or Kanada literature, and so on. I could only start thinking about ancient India, and realized that giving a synopsis of India's cultural contributions would itself take me a lifetime.
Sincere question - are you somebody who actually knows a thing or two about "human culture", other than as a measuring contest? Are you somebody who deeply enjoys any cultural pursuits? If so, there is a wealth of literature and poetry and music and art to enjoy that India has produced over millenia - far more than you can enjoy in a few lifetimes. I would be happy to nudge you in a few directions, depending on your tastes.
But if this is just a "You no culture, we lots of culture" thing, please don't waste my time.
(Given that you asked the question you asked, I think I know which camp you fall into.)
Non sequiter.