By Harry Robertson, Ankur Banerjee and Alden Bentley NEW YORK/LONDON/SINGAPORE (Reuters) -The dollar fell to a three-month low on Tuesday as concerns about slowing growth and the impact from tariffs on the U.

President Donald Trump’s long-threatened tariffs against Canada and Mexico finally went into effect Tuesday, putting global markets on edge and setting up costly retaliations by the United States’ North American allies.

Canadian and Mexican imports to the United States will now by taxed at 25%, while duties on Chinese imports will be doubled to 20%.