There is an institutional gap in rural areas, and thus it is difficult to implement the green rating for integrated habitat assessment (Griha) scheme in those areas, said Nobel prize laureate Rajendra Pachauri, who is also director of The Energy and Resources Institute (Teri). He was talking to media persons on Wednesday after a meeting with Confederation of Real Estate Developers’ Associations of India (Credai) members on environmental issues and eco-housing.