( CNN ) -- I strongly believe being mayor is the public post in which you have the greatest opportunity to change peoples ' lives for the better . People live in cities , not states or nations . As a mayor , you are connected directly to citizens . And cities are increasingly the preferred place for most people to live . Today , half of the world 's population is settled in urban areas . By 2050 , seven out of 10 people will live in cities , according to United Nations projections . I like to say I have the best job in the world . Rio is an incredible place , a vibrant place , full of energy , culture and virtues . In the recent past , the city and its people seemed to be be headed down -- after 1960 , Rio was was no longer the capital of Brazil and it faced economic difficulties and bad public management , which helped aggravate urban problems such as poverty and violence . Watch Eduardo Paes ' TED Talk . But those days are over , and that 's symbolized by the fact that Rio will host the fist Olympic Games in South America in 2016 . It was not easy to get there . Our Olympic bid had to be selected over strong candidates such as Madrid , Tokyo and Chicago . But the International Olympic Commitee found our proposal was the one that would leave the greatest legacy . With dedication , inspiration and professionalism we have shown that things can be done . TED.com : Jaime Lerner sings of the city . Running a city is a great challenge . But it turns out that you do n't have to be powerful or rich to be innovative and find good forms of urban development . I believe there are four basic commandments that serve as pillars for building a better city : . Commandment 1 -- A city of the future has to be environmentally friendly . Rio is an energetic , vibrant place , full of beauty and nature . But we face the kinds of problems any developing metropolis does -- with pollution , traffic congestion , poverty . Distribution of green areas , for example , is not uniform . Madureira , the heart of the suburb in Rio , is a concrete jungle . You have to find open spaces and make it so people can get to them . We are building the third-largest park in the city in Madureira , the temperature will drop 2 to 3 degrees centigrade . Every time you think of a city you have to think green , green , green . Commandment 2 -- A city of the future has to deal with mobility and integration . Cities are packed with people . How can you move people around effectively ? High-capacity transportation usually requires a lot of money . A solution we found was Bus Rapid Transit ( BRT ) , presented by a former mayor of Curitiba , Jaime Lerner . You transform a bus so that it functions virtually as a train car , with dedicated lanes and the same comfort and features as a subway station . A kilometer of BRT costs 10 times less than a subway and it gets built much faster . We will see the proportion of Rio 's population served by high capacity transportation rise from 18 % today to 63 % by 2015 . TED.com : Why the world needs charter cities . Commandment 3 -- A city of the future has to be socially integrated . In Rio , 1.4 million of the 6.3 million people live in favelas , or slums . They are all over the city but favelas are not always a problem -- sometimes they can be a solution , if you have the right public policies . What you need is to change from a vicious circle to a virtuous circle : Bring basic services inside the favelas with the same high quality you have in richer areas . The second aspect is to create open space in the favelas and develop infrastructure . By 2020 , Rio aims to have all its favelas completely urbanized . Commandment 4 -- A city of the future has to use technology . We use technology to be flexible . In Rio we built a Center of Operations , a situation room that gathers information from municipal departments and allows us to manage and help decision-making . I can check the weather , the traffic and the location of city 's waste collection trucks . Each of 4,000 buses in the city has a camera connected to the situation room . That help us manage emergencies and extreme situations . At the end of the day , when we talk about a city we are talking about a gathering of people . We can not see that as a problem . The city of the future is a place that cares about its citizens and brings them together .
Eduardo Paes : More than half the world 's people now live in cities . Paes : Cities must be environmentally friendly , must find answers to congestion , pollution . Rio is using `` bus rapid transit '' as an alternative to building costly subway lines , he says . Comment: