Around 64% of water and sanitation networks need complete repair or replacement. Insufficient metering, which does not charge for actual consumption, and low tariffs discourage utility companies from making the substantial investments required to renew and modernise the networks. The two main sources of air pollution are industrial and energy plants and individual motor vehicles. Although concentrations of particulate matter were lower in 2011 than in other upper-middle income countries, they are expected to rise quickly in large cities, given the rapidly increasing motorisation rates.