Sharma developed a metal attachment called the Kaalink that attaches to the exhaust pipe and captures soot while allowing exhaust gases to escape. This left the question of what to do with the captured soot. He then figured out that he could use that soot to create everything from pen ink to outdoor paint. The exhaust device is now produced by a company called Graviky Labs, and the ink is produced by its subsidiary, Air Ink. Sharma is involved with both companies.
Fast Company highlights that Sharma's enterprise is still quite small, but he and his partners are working on expanding it. One way the company plans to expand is with a Kickstarter that will give people in the US a chance to buy the pens. Funds from the Kickstarter will purchase the product and help expand the business. The company also partnered with a beer company, but we don't want to spoil anymore details. Instead, go check out the whole story at the Fast Company website. You can also check out Air Ink's Kickstarter here.