As Muslims, we should all bear in mind that the Prophet (peace and blessings be upon him) said, “Prayer is the cornerstone of religion…” Prayer stands as the second pillar of Islam after testifying that there is no god but Allah and Muhammad is His final Messenger. The Prophet (peace and blessings be upon him) said, “Islam is built upon five pillars: testifying that there is no true god except Allah and that Muhammad is the Messenger of Allah, performing Prayer, paying the Zakah, making the pilgrimage to the Sacred House (Hajj), and fasting the month of Ramadan.” (Reported by Al-Bukhari)

Prayer has a certain time in which a Muslim should offer it. Allah says, “Worship at fixed hours hath been enjoined on the believers.” (An-Nisa’: 103). Also, the Prophet (peace and blessings be upon him) warned against ignoring to offer Prayers in their due times.
Sheikh Ahmad Kutty, a senior lecturer and Islamic scholar at the Islamic Institute of Toronto, Ontario, Canada, states: “While we are not allowed to combine `Asr and Maghrib, we can, however, combine Zuhr and `Asr in this case. I would urge you to do so if you have any reasonable doubt that you would not be able to make it home before the expiry of time for `Asr. So have no guilt feeling about combining Zuhr and `Asr in this case. Pray `Asr as soon as you have finished praying Zuhr. While doing so, make the intention to combine the two prayers (jam`). While stating this, I must caution you against making it a habit by doing it under normal circumstances.
While mentioning the permissibility of jam` (combining prayers), it is important to know that we are not allowed to combine Fajr with Zhuhr, or `Asr with Maghrib or `Isha’ with Fajr; rather we are allowed only to combine Zhuhr with `Asr (by praying both of them either at the time of the first Prayer or at the time of the second one). Likewise, we are allowed to combine Maghrib with `Isha’ (by praying them both either at the time of the first or the second).
The permissibility of combining Prayers—besides travel, rain, snow storm, sickness, or war—extends to exceptional circumstances as well. Certain obvious examples are: When one is stuck in a traffic jam, or a surgeon is performing an operation lasting hours, or a person is working in an assembly line and cannot leave his job in time for each prayer, et cetera. In such circumstances, one is allowed to combine the prayers in the order we have described.
This ruling is based on a report from Ibn `Abbas that states that the Prophet (peace and blessings be upon him) combined Zuhr and `Asr, and Maghrib and `Isha’ without any reason of war or sickness, or rain, etc.; when he was asked why he had done so, he replied, “He did so in order not cause undue hardship on his people.” In other words, he did so in order to teach us that we are allowed to do so in exceptional circumstances.
Let me conclude by saying: Don’t delay `Asr until Maghrib; rather pray it after Zhuhr, but don’t do so while sitting comfortably at home.”