A 22-year-old woman allegedly killed her four-year-old daughter with the help of her sister in Namakkal district in Tamil Nadu on the evening of Sunday. The woman M. Sneha, who hails from Gandhipuram near Senthamangalam, her husband Muthaiah, 25, and their daughter Poovarasi lived in Chennai. According to the police, Sneha allegedly had an extra-marital affair with a person named …