The Economic Times

Qutub Minars iconic 1600-year-old iron pillar is still completely rust-free. IITians decode the ancient science behind its evergreen surface

A 1600-year-old iron pillar in New Delhi remains remarkably rust-free, baffling scientists for centuries. Researchers discovered its resilience stems from its wrought iron composition, high phosphorus content, and a unique forge welding technique. A protective layer of misawite on its surface further shields it from environmental degradation.