If you live in Pyrmont and have allergies, then the pollen of the plane tree is probably not your friend at the moment. It might seem odd, but a practice centered around breathing, like yoga, is exactly what you need when you feel all stuffed up.
Nasal chest breathing in conjunction with various yoga poses may help to clear the passages that are blocked and increase lung capacity. Alternate nostral breathing (a pranayama practice) can directly work to clear the nose and head.
While it’s hard to breath through the nose in Downward Dog, the release you feel when you come back to standing is draining trapped mucus from the nasal passages. Back-bends may help alleviate tension created in the rib cage from blocked breathing, blowing and coughing, opening the chest and improving breathing capacity.
Shoulderstand and other inversions also promote drainage and opening of nasal passages, as well as alleviating tension the upper back and neck. Matsyasana (fish pose in the shoulder stand sequence) also stimulates the thymus gland, regulating the lymphatic system to support the immune system. A small 2010 study also found that yoga may reduce inflammation in the body which can directly ease allergy symptoms, but there is also evidence that inflammation can be triggered by stress, and so yoga reduces stress and therefore inflammation, and so on.
So get back on the mat and, with the guidance of your teacher, allow yoga to help heal and nurture you during the changing seasons, as in all of life.