Kanika Tekriwal, 27, India

After being diagnosed with cancer in her early 20s, Kanika Tekriwal was determined to make her mark. She established India's first and only marketplace for private jet and helicopter charters.

Her words of advice for anyone wanting to start a business: "Use every 'no' as a stepping-stone to success. Turn every 'no' into a 'yes' through your journey."

You can find our 30 entrepreneurs talking about their experiences in under 30 seconds each on our 30under30 special report .