The Supreme Court on Wednesday directed the Centre to come out with proper guidelines within two weeks to blacklist builders, contractors and architects found to have constructed buildings against sanctioned plans.A bench of Justice Madan B. Lokur and Justice Deepak Gupta said that from now on the owner(s) of illegal or encroached constructions would be given only 48-hour notice to show cause why the building not be sealed or demolished and action shall be taken immediately thereafter.The court directed that wherever any unauthorised/illegal construction come to the notice of the authorities, it "should be stopped with immediate effect".The bench also sought the personal presence of councillor Mukesh Suryan, Chairman of the Najafgarh Wards Committee, after the bench was told that he prevented the officers from carrying out the sealing drive in the area.The court asked the authorities concerned to file affidavit on the allegation that Deputy Commissioner Vishwendra Singh was transferred at Suryan's behest. The authorities, however, maintained that it was a routine transfer.The top court asserted that the sealing drive will continue in Delhi.It directed Delhi Police to ensure adequate protections to officers involved in the sealing of illegal and unauthorised buildings.The court was hearing pleas relating to the validity of the Delhi Laws (Special Provisions) Act, 2006 and subsequent legislation that protected unauthorised constructions from sealing.The sealing drive in Delhi is being carried out by a Supreme Court-appointed Monitoring Committee against business establishments using residential properties for commercial purposes. It is being implemented by the three BJP-led Municipal Corporations of Delhi.The committee was set up by the Supreme Court in 2006. In 2012, the apex court asked the committee to stop the drive. But in December 2017 it ordered resumption of the drive.