Lucknow, July 30 -- Two boys drowned and two sisters were rescued after a sudden surge in a hill stream swept away four children near the India-Nepal border in Shravasti district on late Tuesday, police said on Wednesday. The incident occurred in Sirsiya police station limits. Police said siblings Shahnaz (12), Gulnaz (10) and their brother Shahre Alam (7) had gone to graze goats near the Dhanuha check dam along with neighbour Mukhtar (8). The children entered the nearby Ganjari hill stream to bathe when the water level rose abruptly. Officials said heavy rainfall in the Nepal hills triggered a sudden increase in the stream's flow, catching the children off guard and dragging them into the current. Hearing their cries, local resident Asgar Ali rushed to the spot and, after a strenuous effort, rescued Shahnaz and Gulnaz. However, Shahre Alam and Mukhtar were swept away....