cookies not deleting

am currently in india and am very careful as to cache, tracking , plugins etc.... after removing cookies "bcp.gov.in" it keeps returning, w/o being on line.....i dont like the implications nor the intrusion (thinking about a vpn but if this is coming through the router im not sure it will work) ....the provider is bsnl, a hybrid a private / govt enterprise that recently has been inserting adverts into customer base w/o permission, have been able to block w/ u block...but blocking ads~being tracked are two different things....am using up to date el capitan on late 2015 imac any thoughts.....
thanks
.d