CPI-M General Secretary Sitaram Yechury on Sunday blamed the "systematic dilution" of environmental laws by the Narendra Modi government for the "deadly pollution" in Delhi and said it was a warning for the rest of the country."Deadly pollution in Delhi is a warning for the rest of India. Environmental laws have been systematically and regularly diluted by the Centre," Yechury said on twitter. "Public health warrants progressive laws and their just implementation, unlike what we have witnessed in the last 2.5 years from the Centre," added the Communist Party of India-Marxist leader. Thick smog continued to shroud Delhi on the day as PM 2.5 shot up to the maximum level of 500 across the national capital, reducing the visibility to only 200 metres in the early hours.The Delhi government declared all schools to be shut for three days and banned construction work for five days in the national capital as part of steps to fight pollution.