they're willing to die for it, on this fossil fuel front line. sapna has been living in this village all her life. she shows me something extraordinary. oh, my god, that's actually really hot. you can see the steam coming off of it. she's terrified the heat, from the mine under the ground, will swallow her home like it's destroyed others around her. mining is not about old problem in india. it's a modern one, and it's going to be a future one, because they're expanding all the time. so this is the reality of coal mining in india. 70% of india's energy comes from coal, making it the world's third biggest polluter behind china and the u.s. but its energy needs are set to rise faster than both over the next 20 years. with so many yet to be lifted out of poverty, the potential for emission levels to explode is clear. this is sensitive for officials here, who at one point tried to stop us filming these conditions. >> we can't film until we have authority from high. >> reporter: fine. what were all those people doing there? >> the process is, they are