Prime Minister Nawaz Sharif Friday blamed sit-ins for delaying the construction of powerhouses in the country, as ricketer-turned-politician Imran Khan continued protesting with supporters in the capital city for over two months.While presiding over a special cabinet meeting, Sharif reviewed the performance of three ministries including railways, petroleum and planning and development, Geo News reported.Tahirul Qadri-led Pakistan Awami Tehreek (PAT) and Imran Khan-led Pakistan Tehreek-e-Insaf (PTI) launched their anti-government protests Aug 14. While Imran Khan continues his agitation, the PAT wrapped up its sit-in Oct 21 after 70 days.Khan is set to stage a rally outside the Election Commission of Pakistan (ECP) building Tuesday to protest "poll rigging".