Exactly how widespread is the presence of poisonous arsenic in the groundwater that Indians drink? In Delhi, a doctor's phone call propels Down To Earth to visit Uttar Pradesh's Ballia district. 950 kilometres away from the country's capital, we found village after village affected, effectively re-drawing the country's arsenic contamination map. Exactly how concerned is the government about this insidious pandemic? In Delhi, institutions set up to guarantee safe water to India's citizens, or monitor its quality, brazenly pooh-poohed the problem away. 950 kilometres away, in Ballia town, state officials -- in arrogant tandem -- were equally in denial. RITU GUPTA walks the new arsenic trail: