Short answers, pulled from the story.
The Siege of Malta lasted from June 1940 to November 1942, a period of approximately two and a half years. The siege ended when the Axis diverted forces to the Tunisia campaign following the Allied landings in North Africa in November 1942.
Malta was the only Allied base between Gibraltar and Alexandria, Egypt. Aircraft and submarines based on the island could attack Axis ships supplying Rommel's forces in North Africa. General Erwin Rommel warned in May 1941 that without Malta the Axis would end by losing control of North Africa.
The German Luftwaffe and Italian Regia Aeronautica flew a total of 3,000 bombing raids over two years, dropping 6,700 tons of bombs on the Grand Harbour area alone. Between the 20th of March and the 28th of April 1942, the Germans flew 11,819 sorties and dropped 6,557 tons of bombs in a single concentrated campaign.
When Italy declared war on the 10th of June 1940, Malta's entire fighter defence consisted of six obsolete Gloster Sea Gladiator biplanes, with another six in crates. Ten of the crated Gladiators were assembled and named Faith, Hope, and Charity. The pilots were flying boat aircrew with no experience of fighter operations.
Operation Pedestal was a convoy operation in August 1942 that brought vital supplies to the besieged island. Of 14 merchant ships sent, nine were sunk along with the aircraft carrier HMS Eagle, one cruiser, and three destroyers. Only five merchant ships reached Malta, but the supplies they carried were critical to sustaining the garrison.
Air Vice Marshal Keith Park replaced Hugh Lloyd as AOC on the 14th of July 1942. Park issued his Forward Interception Plan on the 25th of July 1942, sending Spitfires to intercept Axis formations before they reached the island rather than fighting defensively over it. The plan forced the Axis to abandon daylight raids within six days and the Ju 87 Stuka was withdrawn from operations over Malta altogether.