Road transport & highways minister Kamal Nath has asked Canadian pension funds and financial institutions to invest in Indian highway sector, which require a total investment of $70 billion by the end of 2011-12. The private sector has to contribute nearly $45 billion through public-private partnership. The appeal was made during Nath?s meeting with long-term debt as well as equity investors, including Empire Financial Group, Aviva Investors, Aegon Capital Management Incorporation and Ontario Teachers Pension Plan Board, in Toronto, an official release said on Thursday.