Cities play an important role in social and economic activities. Cities generally perform poorly in terms of environmental performance (compared to social and economic activities). One of the main reasons behind this poor environmental performance appears to be due to population pressure and its impacts on the environment. Currently, about 50% population live in cities which is projected to rise in the coming years (by 2050 it could 6 out of 10 people will live in cities). Most of world megacities (> 10 million people) are in developing countries (e.g. Guangzhou, Shanghai, Jakarta, Seoul, Delhi, Mexico, Karachi, Manila, Sao Paulo, Mumbai, Beijing, Moscow, Dhaka, Cairo, Kolkata, Buenos Aires, Bangkok, Istanbul, Lagos, Tehran, Rio de Janeiro, Shenzhen and Tanjin) and few are in developed countries (Tokyo, New York, Los Angeles, Osaka, London, Rhine-Ruhr, Paris). The dense population in cities generate huge volume of solid and soluble wastes, the demand for electricity, water and traffic in cities will cause significant carbon footprints and water footprints. What measures would be needed so that cities remain a healthy place to live on in terms of managing carbon pollution and water pollution in the future?