corrigendum - annual maintenance contract for various civil jobs under civil-iph at btps , annual maintenance contract for various civil jobs under civil-iph at btps . , annual maintenance contract for execution of:- a ) building work ( vol-i ) as per pwdsor ( wc-ii ) govt . of w . b as per relevant books effective from 01 . 11 . 2017 up to 05th addendum & corrigendum w . e . f 16 . 04 . 2019 thereof . b ) sanitary & plumbing work ( vol-ii ) as per pwdsor ( wc-ii ) govt . of w . b as per relevant book effective from 01 . 11 . 2017 up to 02nd addendum & corrigendum w . e . f 04 . 06 . 2018 thereof . c ) roads work , bridge & culverts work and carriage etc . ( vol-iii ) as per pwdsor govt . of w . b for works as per relevant books effective from 30 . 08 . 2018 up to 04th addendum & corrigendum w . e . f 16 . 04 . 2019 thereof . payable quantity will be as per execution at actual and rates for payment will be on the basis of rates given in above wbpwd schedule for different items . , maintenance of aquarium at btps guest house for changing of different types of colour fishes , food , medicine for treatment of water , time to time change of water , maintenance of pumps etc . all charges complete . , differential wage rate to accommodate existing labour ( covered under settlement ) wages at btps with respect to the assumed / estimated wage rate as per wbpdsor , [ difference of rate has been derived based on labour wage as on 01 . 01 . 2019 ] . , gst @ 18% sac code 995429