I just bought a Micra base and removed the air filter to find it is a paper filter saturated with some kind of oil. Yes oil. It's the Nissan 135461HK0A. As for not using oil based air filters I have to disagree with your statement. K&N filters work well and even better when checked & cleaned & re oiled about every 6 to 8 months, not the 50,000 miles they suggest. These filters are a one time purchase of about $60 at most places and since I have not yet purchased the Nissan filter but suspect them to be about $20 US. I think they (k&n) are not a waste of money when comparing to how many times Nissan insists this filter be replaced. As for K&N I've been using these filters for 30 years on various cars/trucks and never had a moments trouble including MAF clogging as suggested in another post. A better filter is made by AEM which does not use oil but is capable of being washed and reused for the life of the vehicle. I have yet to contact AEM for availability of a micra dry filter.
Got email back from distributor of AEM products, no filter available for Nissan Micra.