Hanoi is still faced with the problems associated with increasing urbanization. Although it is a major transport hub with a large network of national routes, expressways, railways, and is home to Noi Bai International Airport, the busiest airport in Vietnam, the disparity of wealth between the rich and the poor is a problem in both the capital and throughout the country. Hanoi's public infrastructure was assessed as in poor condition with high amounts of pollution and congestion in 2001. The city also has frequent , air and water pollution, difficult road conditions, traffic congestion, and a rudimentary public transit system. Traffic congestion and air pollution are worsening as the number of motor cycles increases. Squatter settlements are expanding on the outer rim of the city as homelessness rises (2001).