The Thimphu Structure Plan is a modern urban development plan for the Thimphu city, evolved in 1998, with the objective of protecting the fragile ecology of the valley, including its rivers and forests. This planning was necessitated due to growth of automobiles and pressure on the public health infrastructure in the town centre, restrictions imposed on plot coverage and building heights. The plan was approved by the Council of Ministers in 2003. An elected body, the Thimphu Municipal Corporation, is implementing the plan, drawn up by the American architect Christopher Charles Benninger. This plan is estimated to cost more than $1 billion when completed. Funds for implementation of the plan are being provided by the World Bank and the Asian Development Bank.  There are some disputed areas between land owners and stakeholders, which has resulted in the World Bank and the Asian Development Bank requesting the Ministry of Works and Human Settlement (MOWHS) to resolve the issues through a process of the agreement, before further funds are released.