Listed here are well-known inventions and discoveries that are accepted universally.
Zero and the number system: Around 458 AD, Hindu astronomer and mathematician named Aryabhata created a symbol for zero. Mathematical operations like addition and subtraction started using zero, which became globally recognized as a number of its own. The decimal place-value number system was also invented in India between the 1st and 6th centuries.
Buttons: Excavations have revealed the existence of buttons used for ornamental purposes. They were made of shells with two holes at the center.
Cataract surgery: The first cataract surgery was performed by the ancient Indian physician Sushruta, way back in 6th century BCE. To remove the cataract from the eyes, he pushed the lens and used a curved needle to remove it, which was then kept immersed in warm butter for a few days till it healed. People from other countries came to India to seek treatment from Sushruta.
Various medical treatments: Indians were the first to identify leprosy and many remedies for this disease. The treatment to remove stones or the lithiasis treatment was first introduced in India. Historical studies have shown that in the 8th century, a well-known scholar discussed the symptoms and ways of immunization against smallpox. Ancient and alternative methods of treatment are still used for holistic healing.
Shampoo: The Nawabs of Bengal around 1762 used head massage oil that was referred to as champo.
Diamonds: Huge deposits of diamonds were mined from alluvial soil alongside rivers in central India almost 5,000 years ago. Gradually, they were developed into precious stones.
First flush: The Indus Valley Civilization that existed in India over 5,000 years ago had highly advanced canals, along with irrigation, water management, and sewage systems. The world’s first flush toilets were also discovered in most homes in the Indus Valley Civilization.
Steel and metal works: Indians were also pioneers in metallurgy. High quality steel was produced in India almost 2,000 years ago. They produced a seamless celestial globe for the first time.
Systematic organized education system: Ancient universities introduced a systematic education system. India had some residential schools with hostels where a single teacher taught several students at a time.
Source: Interesting Indian Inventions and Discoveries That Are Universally Accepted