Compressed air engines use the energy of compressed air to do useful work. Various grassroots innovators from different parts of the country have approached the problem of non-renewable energy in their own way. They have independently conceived and worked on the concept of compressing air and using it to run engines. Some have operated scooters and motorcycles, some others four-wheelers while some only have a proof of concept. No matter what stage the technology may be in, it shows that the grassroots people do not suffer disadvantage when it comes to imagining the technologies of the future.