A BOMB planted by suspected Sikh militants in a crowded market near a police post exploded Wednesday, killing six people and wounding 30, police said in Amritsar, India. . . . ENGINEERS worked through the night readying the shuttle Atlantis for blastoff Friday, the first of three planned launches in just eight weeks as NASA struggles to kick off its 1991 campaign after delays earlier this year. Atlantis skipper Steven Nagel and co-pilot Kenneth Cameron planned to practice landing procedures early Wednesday. . . . A CATHOLIC taxi driver was killed in northern Belfast, Northern Ireland, early Wednesday by people suspected of belonging to a Protestant paramilitary group, which also set the vehicle on fire.