I was always embarrassed by sanitary towel adverts on telly – to my daughter’s disapproval. Then, in February this year, I went to India as part of a Pepal’s management development programme, and was allocated to a group looking at feminine hygiene. I discovered a fascinating world of cultural taboos, brave and ingenious entrepreneurs, ecological, social and economic dilemmas. My latest blog for MIT’s Colab Radio describes the problem, and some beautiful solutions.