TRAGEDY: People gather at the accident site in Korba, some 200 km from Raipur, Chhattisgarh, on Wednesday.

KORBA (CHHATTISGARH): At least 20 labourers were killed and nearly 70 are feared trapped under debris after a chimney at an under-construction thermal power plant of the Bharat Aluminium Company Limited (BALCO) caved in here on Wednesday.