As Amazon and Walmart-owned Flipkart spend billions to make a dent in India’s retail market, the two companies have stumbled upon a new challenge: Mukesh Ambani, Asia’s richest man. Reliance Retail and Reliance Jio, two subsidiaries of Ambani’s Reliance Industries, said they have soft launched JioMart , their e-commerce venture, in parts of the state of Maharashtra — Mumbai, Kalyan and Thane. The e-commerce venture, which is being marketed as “Desh Ki Nayi Dukaan” (Hindi for new store for the country), currently offers a catalog of 50,000 grocery items and promises “free and express delivery.” In an email to employees, accessed by TechCrunch, the two aforementioned subsidiaries that are working together on the e-commerce venture, said they plan to expand the service to many parts of India in coming months. A Reliance spokesperson declined to comment. The soft launch this week comes months after Ambani, who runs Reliance Industries — India’s largest industrial house — said that he ...