That's the practice where traders buy ahead of large orders from ETFs and short sell ahead of large sell orders. (seekingalpha.com)
If you are not familiar with placing stock or ETF trades, it can be a bit stressful if you are placing large sell orders. (moneysmartsblog.com)
However, if a particular ETF is not so popular and there are very few buyers or seller in the secondary market, in such case, if there is large buy order, price of an ETF may go up to Rs. 110 / 115 per unit and if there is large sell order price of an ETF may go down to Rs. 85 / 90 per unit. (passivefunds.in)