What potential consequences could result from the collision between the Soviet satellite and Chinese rocket booster?

If the defunct Soviet satellite (from 1989) and Chinese rocket booster (from 2009) collide, it would be the first spontaneous collision between space debris in over a decade and could increase the amount of space junk around Earth by 10-20%. The collision would produce numerous additional debris fragments, contributing to the growing problem of space waste. Experts fear this scenario because it represents a significant escalation in the space debris challenge, potentially threatening operational satellites and future space missions.