Explanation:

 Justification: Statement 2: An ingenious method was devised of downward distillation of the zinc vapour formed after smelting zinc ore. The text Rasaratnakara describes this technique of Zinc production. Another remarkable artistic innovation by Indian metalworkers of the past was the use of zinc in making highly elegant bidri ware, an inlayed zinc alloy, which came into vogue under the Muslim rulers of the Bidar province in the Hyderabad region from about the 14th century.
Statement 3: The pillar has attracted the attention of archaeologists and materials scientists and has been called "a testament to the skill of ancient Indian blacksmiths" because of its high resistance to corrosion. The corrosion resistance results from an even layer of crystalline iron hydrogen phosphate hydrate forming on the high phosphorus content iron, which serves to protect it from the effects of the local Delhi climate
Statement 4:India has been reputed for its iron and steel since Greek and Roman times with the earliest reported finds of high-carbon steels in the world coming from the early Christian era.
? Wootz is the anglicized version of ukku in the languages of the states of Karnataka, and Andhra Pradesh, a term denoting steel.
? Studies on Wootz indicate that it was an ultra-high carbon steel with between 1-2% carbon and was believed to have been used to fashion Damascus blades with a watered steel pattern.
? Literary accounts suggest that steel from the southern part of the Indian subcontinent was exported to Europe, China, the Arab world and the Middle East.