A large portion of the world?s tanning industry operates in low- and middle-income countries, and the percentage of these countries contributing to light and heavy leather materials increased from 35% to 56% and 26% to 56%, respectively, between 1970 and 1995. Many of these tannery sites are clustered together, creating heavily polluting industrial areas in many countries. These pollutants are responsible for the contamination of all nearby surface and groundwater systems with severely high levels of chromium The discharge of solid waste and wastewater containing chromium is the main environmental problem of tannery industry. Chromium is a highly toxic compound and the dumping of chromium containing material is in most countries restricted to a few special dumping grounds. Emissions into the air are primarily related to energy use, but also the use of organic solvents and dyes causes emissions into the air.