Short answers, pulled from the story.
Adolf Hitler declared that Leningrad must die of starvation in a speech at Munich on the 8th of November 1941. The German High Command viewed the capture of this city as one of three primary goals within Operation Barbarossa, the massive invasion of the Soviet Union launched on the 22nd of June 1941.
Over 1,400,000 civilian evacuees including 414,148 children moved between the 29th of June 1941 and the 31st of March 1943 using these routes. They were relocated to the Volga area, the Urals, Siberia, and Kazakhstan.
From November 1941 to February 1942 the only food available was 125 grams of bread per day containing 50, 60% sawdust and other inedible admixtures. Deaths peaked in January and February 1942 at 100,000 people per month mostly from starvation.
By the 8th of September, German forces had largely surrounded the city, cutting off all supply routes to Leningrad and its suburbs. The last rail connection to Leningrad was severed on the 30th of August 1941 when German forces reached the Neva River.
Military historian Victor Davis Hanson affirms that more than one million died amid mass starvation epidemic cannibalism and daily barrages greater death toll than any siege in history. Journalist Harrison Salisbury estimated total deaths attributable to hunger over 1,000,000 with overall total between 1.3 and 1.5 million souls.