(This story originally appeared in on Jul 10, 2015)

She wanted to do PhD and become a teacher, but after her father's death she had to take up a job in an MNC. However, Roshni Mukherjee found a way to teach tens of thousands of school students for free.She launched Examfear.com to post video lessons for classes 9 to 12, and her YouTube channel has more than 68,000 subscribers. She has shared around 3,700 videos in the past four years, which means more than two video les sons posted per day ."It began when my maid told me her two children kept failing in their exams be cause teachers in the government school in Tamil Nadu , where they studied, would rarely come to class. These were the children I wanted to reach out to," she said.As technology offered the best solution, she uploaded a video on YouTube, explaining the physics concept of motion. She used a Powerpoint slideshow and a microphone to explain the concepts. As there was a good response, she started posting more video lessons."After seeing the videos, students started asking doubts in the comments section and also requested for video lessons on specific topics. I was happy to help," she said. She spent a few hours on weekdays and all her weekends preparing the videos lessons in chemistry, physics, mathematics and biology .She initially prepared videos for classes 11 and 12, but soon expanded to classes 9 and 10. "I refer CBSE syllabus and brush through ICSE syllabus to add any points I may have missed out. The videos are simple: made on Powerpoint (slide shows) with a voice in the background explaining the concepts," she said.About eight months ago, Roshni quit her job with HP (which she had joined in the meantime) to focus on video lessons. "The channel was starting to make a little money from Google ads and I added a contribute button for those who wished to do so. I plan to keep the videos entirely free because only then can I reach a lot more students," she said.Now, Roshni wants her videos to reach the remotest corners of the country. For this, she has to translate the videos into regional languages."That is the next course of action -making these videos into regional languages such as Kannada, Tamil and Bengali," she said.Over time, Roshni hopes to expand her classes to junior grades and also subjects such history and geography .