Holcim Ltd.’s open offer for Gujarat Ambuja Cements Ltd. , which was scheduled to open on March 25, will be delayed by a few days, a source close to the offer said on Friday.  Holcim had bought a 14.8 per cent stake in Gujarat Ambuja for 21 billion rupees in January and had offered to buy up to 20 per cent more from public shareholders at 90.64 rupees each. The source did not indicate the reason for the delay.