Annual emissions of anthropogenic Hg to the atmosphere in different regions of the world during the last decade show an interesting dichotomy: the emissions in the developed countries increased at the rate of about 4.5–5.5% yr−1 up to 1989 and have since remained nearly constant, while in developing countries the emissions continue to rise steadily at the rate of 2.7–4.5% yr−1. On a global basis, however, the total anthropogenic emissions of Hg increased by about 4% yr−1 during the 1980s, peaked in 1989 at about 2290 t and are currently decreasing at the rate of about 1.3% yr−1.

To clear the persistent ambiguity governing the concept of sustainable development of urban centres, attention must be paid to present and future human needs

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Will the future city, marked by responsible governance and a concerned citizenry, be able to address the problems dogging the world's urban centres?