Large areas of tropical forest are converted to palm oil plantations each year. Palm oil is widely used in the food industry and also in the production of soap and beauty products. The petition asks that a new "palm oil tax" be applied to products containing palm oil, to disincentivise its use.
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I have written to many companies in the past asking for clarity on their palm oil use to no avail. Many supermarkets are committed to palm oil reduction but it is really the large manufacturers that are the problem.