The Congress on Tuesday slammed the Delhi government over the "astronomical" hike in water charges, saying the AAP government has been breaking all its poll promises ever since it came to power."The decision to increase the water charges was a retrograde step," Delhi Congress Chief Ajay Maken told reporters here.The Delhi Jal Board, earlier in the day, increased a combind water and sewer tariff in the city by 20 per cent, which applies to only those who consume more than 20,000 litres of water per month.Maken said that in 2015, days after coming to power, the Aam Aadmi Party government had hiked the water tariff by 10 per cent for consumers falling in the same category. "The Kejriwal government has hiked the water charges to an astronomical 30 per cent within three years after coming to power to negate its hollow claim of providing free water to the citizens of Delhi," he said.The former Union Minister also said that the latest hike comes three months after Delhi Chief Minister Arvind Kejriwal "took the ministerial portfolio of water". Maken said like all other promises of Kejriwal, giving free water to the residents of Delhi has also proved to be a "hollow promise". "The AAP government has been systematically breaking all its election promises one after another."The Congress leader said that after a hike in the water charges, the Delhi government would now increase the electricity tariff."The Kejriwal government seemed to be the least concerned about the welfare of the people of Delhi, who elected him to power with absolute majority after believing in the false election promises his party (AAP) made to them, though he has been breaking all those promises with impunity," he said.