Complex sentence: Only Bangalore had a sewer tariff of US $0.02 per m3, while the other three cities did not charge for sewerage, although the better-off tend to be the ones with access to sewers.
Split into simpler sentences: Only Bangalore had a sewer tariff of US $0.02 per m3. The other three cities did not charge for sewerage, although the better-off tend to be the ones with access to sewers.