The World Bank, under its Clean Air Project, is building many footover (pedestrian) bridges in Dhaka. This is wrong on at least two counts. The point of footover bridges is to facilitate the movement of cars, which pollute. Meanwhile, they hinder the movement of pedestrians, who do not. Efforts to improve air quality should focus on improving the situation of non-motorized transport, including walking. It does not make sense to penalize pedestrians in the name of clean air. In fact, street-level crossings (zebra crossings or crosswalks) would help to smooth ear traffic; as it is, cars rush to the next stoplight, only to sit and wait. Most cities around the world have stopped building footover bridges and torn down existing ones, as they are extremely unpopular with pedestrians, do not reduce accidents, and do nothing to smooth traffic flow.
Second, it is the World Bank's policy that all new transport projects must incorporate Universally Accessible Design. There is no way that a person in a wheelchair, or most people with a disability, or even someone with a fairly minor problem walking, can use a footover bridge. A bridge equipped with an escalator is still unusable by a person in a wheelchair. It is obviously completely impractical to create bridges with lifts (elevators) throughout the city. Nor is there any reason to do something so wasteful and likely to land up broken and thus useless within a short period. Zebra crossings make street crossings easier for all users, and thus contribute to independent movement by all, as well as contributing to clean air.