LEDs are highly efficient light sources that emit light when electric current passes through semiconductor materials. They consume less energy than incandescent bulbs and have a longer lifespan since they do not have filaments to burn out. While LED chips and packaging require significant capital and technology, assembling finished LED lighting products can be a profitable business with an investment of about INR 35 lakhs. Key factors for LED lighting include construction, driver systems, thermal management, efficiency, color quality, and lifespan.