Most Indian sciences did decline heavily with Muslim and European invasions.
More so Europeans. As cruel and savage Muslims were against the Hindus, they were in high praise of Hindu sciences and allowed them to continue and used Hindu sciences to usher in their scientific revolution in Arabia. The Europeans, however, out of sheer jealousy outlawed Hindu sciences, and then proceeded to plagiaraise everything they could while condemning the source. We know for a fact that the Europeans learned how to make zinc and crucible steel by reverse engineering Indian zinc and steel, and tried to issue patents for it. We also know they stole textile technology and textile methods to improve their own. They also stole the tier based education system from India which imparted mass education to its masses and was divided into school, college and university level, and then out of jealousy shut down the Indian education system. Then, they stole Indian philosophy and this bought about the science of psychology in the West. They also stole from Indian logic to improve their own logic.
New evidence is now emerging they stole calculus from the Kerela school of mathematicans.
And now they are trying to steal Ayurveda and Yoga, and once again condemning the original source. Recently, Western Yoga studios announced Yoga predated Hinduism. And a Western pharmaceutical company tried to patent tumeric as a drug, after clinical trials proved its efficacy. Yet, tumeric is being used in Ayurveda and Indian cooking for thousands of years. No wonder they failed to get the patent.
The West has a lot of bad karma. It is going to pay a price for it sooner or later.