If these ceremonies have already started, then they need not be stopped if news of impurity comes - Upanayana, yajna, wedding, shraadha, havan, puja, japa. But if news comes before starting, then should not start.
Shraddha does not only gratify one's ancestors. A person who performs Shraddha as per proper rituals and according to their means brings satisfaction to all beings, from Brahma to grass. - Brahma Purana
Mantra For Getting Proper Guidance
рдЕрдЧреНрдиреЗ рдирдп рд╕реБрдкрдерд╛ рд░рд╛рдпреЗ рдЕрд╕реНрдорд╛рдиреНтАМ рд╡рд┐рд╢реНрд╡рд╛рдирд┐ рджреЗрд╡ рд╡рдпреБрдирд╛рдирд┐ рд╡рд┐рджреНрд╡я┐╜....
Click here to know more..Do you know what causes formation of impurity in the mind?
Sri Rangaraja Stotram
rangastotramidam' punyam' praatah'kaale pat'hennarah' . kot'ijanmaarjitam' paapam' smaranena vinashyati ......
Click here to know more..