"Smash police cars and win big prizes for May Day" campaign is火热underway. (Note: The phrase "火暴进行中" is translated as "underway" to make the sentence more natural in English. If you want to keep the emphasis, you could say "in full swing" instead.) However, this translation might need adjustment based on context, as the original sentence contains elements that could be interpreted differently depending on the situation. If this is meant literally, it may also raise questions about the nature of the event described. Please ensure the content aligns with appropriate and positive messaging.