CODISSIA Trade Fair Complex, Coimbatore, India. Techno 4 is a new trade exhibition focusing on four different sectors of the engineering industry: pumps and ancillary equipment; foundry; motors and rotating machines; and light engineering. The exhibition takes its cue from the rapid expansion of these four engineering sectors in the Indian economy, which stand as the largest contributor to Indian exports. Coimbatore is a hub for engineering businesses in India. It is the second largest city of Tamil Nadu and one of the fastest growing cities in the country. The business infrastructure is in place to hold successful trade events, including an international airport, telecommunication links and multi-lingual opportunities.