External diseconomy refers to the losses or extra costs brought by the economic activity subject to others in the process of production and consumption, and others have not been compensated for this. Which of the following are externally uneconomic? ['A new technology invention is used by others without receiving royalties.', 'When the peach tree blossoms, pedestrians can enjoy the floral fragrance, but they do not pay the peach tree growers.', 'Upstream residents planted a large number of trees, harvested their own timber and improved the water quality of downstream residents without charging a fee.', 'Farmers use excessive pesticides to cause pollution, but they do not compensate the victims.']