Apart from this, diamonds were also found first in India almost 5000 years back. But the same is not clear as to when were they actually mined. Till the 18th century, India was the sole producer of diamonds until they came to be discovered in Brazil as well. Additionally, even zinc was first recognized as a metal in India. There were zinc mines located at Zawar near Udaipur, Rajasthan during 400BCE. The Charaka Samhita mentioned the medicinal utility of zinc as well.
Coming to the innovations, the following innovations took place:
1. Public bathing: According to John Keay, the Great Bath of Mohenjo Daro was equal to the size of 'a modest municipal swimming pool.' This Great Bath was complete with stairs leading down to the water at each one of its ends. The bath was housed inside a larger and more elaborate building and was used for public bathing.
2. Urban planning: Remains of major Indus cities around 2600 to1900 BCE which is mostly in the present day Pakistan and Western India. They display distinct characteristics of urban planning such as streets crossing each other at right angles, well arranged rows of structures as well as neatly built, covered drainage and sewage lines, complete with maintenance sumps, running along backlines.
Drains in the ancient maritime city of Lothal for example, designed to be able to take out the city's entire domestic sewage and storm-water was mostly underground. Further, they were also built to high levels of uniformity. Such planning is also evident from remains of Mohenjo-Daro. Mohenjo-Daro was a city to the north-west of Lothal. This city appeared to have been built adhering to a complex level of city grid planning. This leads archaeologists to the conclusion that these cities were conceived entirely even before they were actually built. This was the earliest known manifestation of urban planning.
3. Iron working: Iron works were developed in the Vedic period of India. This was around the same time as, though independently of, Anatolia and the Caucasus. Archaeological sites in India, such as Malhar, Dadupur, Raja Nala Ka Tila and Lahuradewa in present day Uttar Pradesh show iron implements in the period between 1800 BCE-1200 BCE.
Early iron objects found in India can be dated to 1400 BCE by employing the method of radiocarbon dating. Spikes, knives, daggers, arrow- heads, bowls, spoons, saucepans, axes, chisels, tongs, door fittings etc. ranging from 600 BCE to 200 BCE have been discovered from several archaeological sites of India.