There's good news and bad news about life in modern cities-first, the bad.People who study population growth predict a nightmare by the year 2025: the global population will be more than 8 billion, and almost 4 billion of these people will be living in cities in developing countries such as India and Nigeria.By the year 2025, population experts predict, 660 million people will be living in cities in India.Nairobi, Kenya, has basic services for 200,000 people but has a population of 5 million.